Function resolver
has 61 lines of code (exceeds 25 allowed). Consider refactoring. Open
export const resolver = async (routes: Path<RouteHandler>, req: IncomingMessage): Promise<{ handler: any, input: Input, action: Action }> => {
routes = {
'/': {
read: (input: Input) => response({ message: 'Not found' }, 404),
write: (input: Input) => response({ message: 'Not found' }, 404),
Function resolver
has a Cognitive Complexity of 7 (exceeds 5 allowed). Consider refactoring. Open
export const resolver = async (routes: Path<RouteHandler>, req: IncomingMessage): Promise<{ handler: any, input: Input, action: Action }> => {
routes = {
'/': {
read: (input: Input) => response({ message: 'Not found' }, 404),
write: (input: Input) => response({ message: 'Not found' }, 404),
- Read upRead up
Cognitive Complexity
Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.
A method's cognitive complexity is based on a few simple rules:
- Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
- Code is considered more complex for each "break in the linear flow of the code"
- Code is considered more complex when "flow breaking structures are nested"
Further reading
Similar blocks of code found in 4 locations. Consider refactoring. Open
'/500': {
read: (input: Input) => response({ message: 'Internal Server Error' }, 500),
write: (input: Input) => response({ message: 'Internal Server Error' }, 500),
},
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 58.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 4 locations. Consider refactoring. Open
'/': {
read: (input: Input) => response({ message: 'Not found' }, 404),
write: (input: Input) => response({ message: 'Not found' }, 404),
},
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 58.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 4 locations. Consider refactoring. Open
'/400': {
read: (input: Input) => response({ message: 'Input params error' }, 400),
write: (input: Input) => response({ message: 'Input params error' }, 400),
},
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 58.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Similar blocks of code found in 4 locations. Consider refactoring. Open
'/404': {
read: (input: Input) => response({ message: 'Not found' }, 404),
write: (input: Input) => response({ message: 'Not found' }, 404),
},
- Read upRead up
Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 58.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76
Missing semicolon Open
return (decode) ? JSON.parse(<string>input) : JSON.stringify(<{[key: string]: any}>input)
- Read upRead up
- Exclude checks
Rule: semicolon
Enforces consistent semicolon usage at the end of every statement.
Notes
- Has Fix
Config
One of the following arguments must be provided:
-
"always"
enforces semicolons at the end of every statement. -
"never"
disallows semicolons at the end of every statement except for when they are necessary.
The following arguments may be optionally provided:
-
"ignore-interfaces"
skips checking semicolons at the end of interface members. -
"ignore-bound-class-methods"
skips checking semicolons at the end of bound class methods. -
"strict-bound-class-methods"
disables any special handling of bound class methods and treats them as any other assignment. This option overrides"ignore-bound-class-methods"
.
Examples
"semicolon": true,always
"semicolon": true,never
"semicolon": true,always,ignore-interfaces
"semicolon": true,always,ignore-bound-class-methods
Schema
{
"type": "array",
"items": [
{
"type": "string",
"enum": [
"always",
"never"
]
},
{
"type": "string",
"enum": [
"ignore-interfaces"
]
}
],
"additionalItems": false
}
For more information see this page.
Missing semicolon Open
}
- Read upRead up
- Exclude checks
Rule: semicolon
Enforces consistent semicolon usage at the end of every statement.
Notes
- Has Fix
Config
One of the following arguments must be provided:
-
"always"
enforces semicolons at the end of every statement. -
"never"
disallows semicolons at the end of every statement except for when they are necessary.
The following arguments may be optionally provided:
-
"ignore-interfaces"
skips checking semicolons at the end of interface members. -
"ignore-bound-class-methods"
skips checking semicolons at the end of bound class methods. -
"strict-bound-class-methods"
disables any special handling of bound class methods and treats them as any other assignment. This option overrides"ignore-bound-class-methods"
.
Examples
"semicolon": true,always
"semicolon": true,never
"semicolon": true,always,ignore-interfaces
"semicolon": true,always,ignore-bound-class-methods
Schema
{
"type": "array",
"items": [
{
"type": "string",
"enum": [
"always",
"never"
]
},
{
"type": "string",
"enum": [
"ignore-interfaces"
]
}
],
"additionalItems": false
}
For more information see this page.
object access via string literals is disallowed Open
action = input['action'];
- Read upRead up
- Exclude checks
Rule: no-string-literal
Forbids unnecessary string literal property access.
Allows obj["prop-erty"]
(can't be a regular property access).
Disallows obj["property"]
(should be obj.property
).
Rationale
If --noImplicitAny
is turned off,
property access via a string literal will be 'any' if the property does not exist.
Notes
- Has Fix
Config
Not configurable.
Examples
"no-string-literal": true
For more information see this page.
Expected property shorthand in object literal ('{input}'). Open
write: (input: Input) => response({input: input, action: 'write'}, 200),
- Read upRead up
- Exclude checks
Rule: object-literal-shorthand
Enforces/disallows use of ES6 object literal shorthand.
Notes
- Has Fix
Config
"always"
assumed to be default option, thus with no options provided
the rule enforces object literal methods and properties shorthands.
With "never"
option provided, any shorthand object literal syntax causes an error.
The rule can be configured in a more granular way.
With {"property": "never"}
provided (which is equivalent to {"property": "never", "method": "always"}
),
the rule only flags property shorthand assignments,
and respectively with {"method": "never"}
(equivalent to {"property": "always", "method": "never"}
),
the rule fails only on method shorthands.
Examples
"object-literal-shorthand": true
"object-literal-shorthand": true,never
"object-literal-shorthand": true,[object Object]
Schema
{
"oneOf": [
{
"type": "string",
"enum": [
"never"
]
},
{
"type": "object",
"properties": {
"property": {
"type": "string",
"enum": [
"never"
]
},
"method": {
"type": "string",
"enum": [
"never"
]
}
},
"minProperties": 1,
"maxProperties": 2
}
]
}
For more information see this page.
Expected property shorthand in object literal ('{input}'). Open
read: (input: Input) => response({input: input, action: 'read'}, 200),
- Read upRead up
- Exclude checks
Rule: object-literal-shorthand
Enforces/disallows use of ES6 object literal shorthand.
Notes
- Has Fix
Config
"always"
assumed to be default option, thus with no options provided
the rule enforces object literal methods and properties shorthands.
With "never"
option provided, any shorthand object literal syntax causes an error.
The rule can be configured in a more granular way.
With {"property": "never"}
provided (which is equivalent to {"property": "never", "method": "always"}
),
the rule only flags property shorthand assignments,
and respectively with {"method": "never"}
(equivalent to {"property": "always", "method": "never"}
),
the rule fails only on method shorthands.
Examples
"object-literal-shorthand": true
"object-literal-shorthand": true,never
"object-literal-shorthand": true,[object Object]
Schema
{
"oneOf": [
{
"type": "string",
"enum": [
"never"
]
},
{
"type": "object",
"properties": {
"property": {
"type": "string",
"enum": [
"never"
]
},
"method": {
"type": "string",
"enum": [
"never"
]
}
},
"minProperties": 1,
"maxProperties": 2
}
]
}
For more information see this page.
Type assertion using the '<>' syntax is forbidden. Use the 'as' syntax instead. Open
return (decode) ? JSON.parse(<string>input) : JSON.stringify(<{[key: string]: any}>input)
- Read upRead up
- Exclude checks
Rule: no-angle-bracket-type-assertion
Requires the use of as Type
for type assertions instead of <Type>
.
Rationale
Both formats of type assertions have the same effect, but only as
type assertions
work in .tsx
files. This rule ensures that you have a consistent type assertion style
across your codebase.
Notes
- TypeScript Only
- Has Fix
Config
Not configurable.
Examples
"no-angle-bracket-type-assertion": true
For more information see this page.
Type assertion using the '<>' syntax is forbidden. Use the 'as' syntax instead. Open
return JSON.stringify(<Data>{
code: decode ? 400 : 500,
status: 'error',
message: 'Invalid JSON'
});
- Read upRead up
- Exclude checks
Rule: no-angle-bracket-type-assertion
Requires the use of as Type
for type assertions instead of <Type>
.
Rationale
Both formats of type assertions have the same effect, but only as
type assertions
work in .tsx
files. This rule ensures that you have a consistent type assertion style
across your codebase.
Notes
- TypeScript Only
- Has Fix
Config
Not configurable.
Examples
"no-angle-bracket-type-assertion": true
For more information see this page.
Identifier 'result' is never reassigned; use 'const' instead of 'let'. Open
let result: Body = codec(req, true);
- Read upRead up
- Exclude checks
Rule: prefer-const
Requires that variable declarations use const
instead of let
and var
if possible.
If a variable is only assigned to once when it is declared, it should be declared using 'const'
Notes
- Has Fix
Config
An optional object containing the property "destructuring" with two possible values:
- "any" (default) - If any variable in destructuring can be const, this rule warns for those variables.
- "all" - Only warns if all variables in destructuring can be const.
Examples
"prefer-const": true
"prefer-const": true,[object Object]
Schema
{
"type": "object",
"properties": {
"destructuring": {
"type": "string",
"enum": [
"all",
"any"
]
}
}
}
For more information see this page.
== should be === Open
'c': (function_name == 'write' && id === false && action in ['default', 'c', 'create', 'new', 'write', 'w']),
- Read upRead up
- Exclude checks
Rule: triple-equals
Requires ===
and !==
in place of ==
and !=
.
Config
Two arguments may be optionally provided:
-
"allow-null-check"
allows==
and!=
when comparing tonull
. -
"allow-undefined-check"
allows==
and!=
when comparing toundefined
.
Examples
"triple-equals": true
"triple-equals": true,allow-null-check
"triple-equals": true,allow-undefined-check
Schema
{
"type": "array",
"items": {
"type": "string",
"enum": [
"allow-null-check",
"allow-undefined-check"
]
},
"minLength": 0,
"maxLength": 2
}
For more information see this page.
== should be === Open
'r': (function_name == 'read' && id !== false && action in ['default', 'r', 'read', 'get', 'one']),
- Read upRead up
- Exclude checks
Rule: triple-equals
Requires ===
and !==
in place of ==
and !=
.
Config
Two arguments may be optionally provided:
-
"allow-null-check"
allows==
and!=
when comparing tonull
. -
"allow-undefined-check"
allows==
and!=
when comparing toundefined
.
Examples
"triple-equals": true
"triple-equals": true,allow-null-check
"triple-equals": true,allow-undefined-check
Schema
{
"type": "array",
"items": {
"type": "string",
"enum": [
"allow-null-check",
"allow-undefined-check"
]
},
"minLength": 0,
"maxLength": 2
}
For more information see this page.
Unnecessary 'await'. Open
return await Promise.resolve(<Data>{
- Read upRead up
- Exclude checks
Rule: no-return-await
Disallows unnecessary return await
.
Rationale
An async function always wraps the return value in a Promise.
Using return await
just adds extra time before the overreaching promise is resolved without changing the semantics.
Notes
- Has Fix
Config
Not configurable.
Examples
"no-return-await": true
For more information see this page.
Array type using 'Array<t>' is forbidden. Use 'T[]' instead.</t> Open
export const BODY_METHODS: Array<BodyMethod> = ['POST', 'PUT', 'PATCH'];
- Read upRead up
- Exclude checks
Rule: array-type
Requires using either 'T[]' or 'Array<t>' for arrays.</t>
Notes
- TypeScript Only
- Has Fix
Config
One of the following arguments must be provided:
-
"array"
enforces use ofT[]
for all types T. -
"generic"
enforces use ofArray<T>
for all types T. -
"array-simple"
enforces use ofT[]
ifT
is a simple type (primitive or type reference).
Examples
"array-type": true,array
"array-type": true,generic
"array-type": true,array-simple
Schema
{
"type": "string",
"enum": [
"array",
"generic",
"array-simple"
]
}
For more information see this page.
== should be === Open
'l': (function_name == 'read' && id === false && action in ['default', 'l', 'list', 'all', 'ls']),
- Read upRead up
- Exclude checks
Rule: triple-equals
Requires ===
and !==
in place of ==
and !=
.
Config
Two arguments may be optionally provided:
-
"allow-null-check"
allows==
and!=
when comparing tonull
. -
"allow-undefined-check"
allows==
and!=
when comparing toundefined
.
Examples
"triple-equals": true
"triple-equals": true,allow-null-check
"triple-equals": true,allow-undefined-check
Schema
{
"type": "array",
"items": {
"type": "string",
"enum": [
"allow-null-check",
"allow-undefined-check"
]
},
"minLength": 0,
"maxLength": 2
}
For more information see this page.
Type assertion using the '<>' syntax is forbidden. Use the 'as' syntax instead. Open
return await Promise.resolve(<Data>{
code: http_code,
status: (http_code >= 200 && http_code < 400) ? 'ok' : 'error',
message: (http_code >= 200 && http_code < 400) ? 'success' : message,
data: !!data ? data : null
- Read upRead up
- Exclude checks
Rule: no-angle-bracket-type-assertion
Requires the use of as Type
for type assertions instead of <Type>
.
Rationale
Both formats of type assertions have the same effect, but only as
type assertions
work in .tsx
files. This rule ensures that you have a consistent type assertion style
across your codebase.
Notes
- TypeScript Only
- Has Fix
Config
Not configurable.
Examples
"no-angle-bracket-type-assertion": true
For more information see this page.
missing whitespace Open
const message = 'message' in data ? data['message']: 'Internal Server Error';
- Read upRead up
- Exclude checks
Rule: whitespace
Enforces whitespace style conventions.
Rationale
Helps maintain a readable, consistent style in your codebase.
Notes
- Has Fix
Config
Several arguments may be optionally provided:
-
"check-branch"
checks branching statements (if
/else
/for
/while
) are followed by whitespace. -
"check-decl"
checks that variable declarations have whitespace around the equals token. -
"check-operator"
checks for whitespace around operator tokens. -
"check-module"
checks for whitespace in import & export statements. -
"check-separator"
checks for whitespace after separator tokens (,
/;
). -
"check-rest-spread"
checks that there is no whitespace after rest/spread operator (...
). -
"check-type"
checks for whitespace before a variable type specification. -
"check-typecast"
checks for whitespace between a typecast and its target. -
"check-type-operator"
checks for whitespace between type operators|
and&
. -
"check-preblock"
checks for whitespace before the opening brace of a block. -
"check-postbrace"
checks for whitespace after an opening brace.
Examples
"whitespace": true,check-branch,check-operator,check-typecast
Schema
{
"type": "array",
"items": {
"type": "string",
"enum": [
"check-branch",
"check-decl",
"check-operator",
"check-module",
"check-separator",
"check-rest-spread",
"check-type",
"check-typecast",
"check-type-operator",
"check-preblock",
"check-postbrace"
]
},
"minLength": 0,
"maxLength": 11
}
For more information see this page.
Shadowed name: 'input' Open
write: (input: Input) => response({ message: 'Internal Server Error' }, 500),
- Read upRead up
- Exclude checks
Rule: no-shadowed-variable
Disallows shadowing variable declarations.
Rationale
When a variable in a local scope and a variable in the containing scope have the same name, shadowing occurs. Shadowing makes it impossible to access the variable in the containing scope and obscures to what value an identifier actually refers. Compare the following snippets:
const a = 'no shadow';
function print() {
console.log(a);
}
print(); // logs 'no shadow'.
const a = 'no shadow';
function print() {
const a = 'shadow'; // TSLint will complain here.
console.log(a);
}
print(); // logs 'shadow'.
ESLint has an equivalent rule. For more background information, refer to this MDN closure doc.
Config
You can optionally pass an object to disable checking for certain kinds of declarations.
Possible keys are "class"
, "enum"
, "function"
, "import"
, "interface"
, "namespace"
, "typeAlias"
and "typeParameter"
. You can also pass "underscore
" to ignore variable names that begin with _
.
Just set the value to false
for the check you want to disable.
All checks default to true
, i.e. are enabled by default.
Note that you cannot disable variables and parameters.
The option "temporalDeadZone"
defaults to true
which shows errors when shadowing block scoped declarations in their
temporal dead zone. When set to false
parameters, classes, enums and variables declared
with let
or const
are not considered shadowed if the shadowing occurs within their
temporal dead zone.
The following example shows how the "temporalDeadZone"
option changes the linting result:
function fn(value) {
if (value) {
const tmp = value; // no error on this line if "temporalDeadZone" is false
return tmp;
}
let tmp = undefined;
if (!value) {
const tmp = value; // this line always contains an error
return tmp;
}
}
Examples
"no-shadowed-variable": true
"no-shadowed-variable": true,[object Object]
Schema
{
"type": "object",
"properties": {
"class": {
"type": "boolean"
},
"enum": {
"type": "boolean"
},
"function": {
"type": "boolean"
},
"import": {
"type": "boolean"
},
"interface": {
"type": "boolean"
},
"namespace": {
"type": "boolean"
},
"typeAlias": {
"type": "boolean"
},
"typeParameter": {
"type": "boolean"
},
"temporalDeadZone": {
"type": "boolean"
},
"underscore": {
"type": "boolean"
}
}
}
For more information see this page.
" should be ' Open
const body = "";//await parseBody(req);
- Read upRead up
- Exclude checks
Rule: quotemark
Enforces quote character for string literals.
Notes
- Has Fix
Config
Five arguments may be optionally provided:
-
"single"
enforces single quotes. -
"double"
enforces double quotes. -
"backtick"
enforces backticks. -
"jsx-single"
enforces single quotes for JSX attributes. -
"jsx-double"
enforces double quotes for JSX attributes. -
"avoid-template"
forbids single-line untagged template strings that do not contain string interpolations. Note that backticks may still be used if"avoid-escape"
is enabled and both single and double quotes are present in the string (the latter option takes precedence). -
"avoid-escape"
allows you to use the "other" quotemark in cases where escaping would normally be required. For example,[true, "double", "avoid-escape"]
would not report a failure on the string literal'Hello "World"'
.
Examples
"quotemark": true,single,avoid-escape,avoid-template
"quotemark": true,single,jsx-double
Schema
{
"type": "array",
"items": {
"type": "string",
"enum": [
"single",
"double",
"backtick",
"jsx-single",
"jsx-double",
"avoid-escape",
"avoid-template"
]
},
"minLength": 0,
"maxLength": 5
}
For more information see this page.
object access via string literals is disallowed Open
delete input['action'];
- Read upRead up
- Exclude checks
Rule: no-string-literal
Forbids unnecessary string literal property access.
Allows obj["prop-erty"]
(can't be a regular property access).
Disallows obj["property"]
(should be obj.property
).
Rationale
If --noImplicitAny
is turned off,
property access via a string literal will be 'any' if the property does not exist.
Notes
- Has Fix
Config
Not configurable.
Examples
"no-string-literal": true
For more information see this page.
Missing semicolon Open
query: Query
- Read upRead up
- Exclude checks
Rule: semicolon
Enforces consistent semicolon usage at the end of every statement.
Notes
- Has Fix
Config
One of the following arguments must be provided:
-
"always"
enforces semicolons at the end of every statement. -
"never"
disallows semicolons at the end of every statement except for when they are necessary.
The following arguments may be optionally provided:
-
"ignore-interfaces"
skips checking semicolons at the end of interface members. -
"ignore-bound-class-methods"
skips checking semicolons at the end of bound class methods. -
"strict-bound-class-methods"
disables any special handling of bound class methods and treats them as any other assignment. This option overrides"ignore-bound-class-methods"
.
Examples
"semicolon": true,always
"semicolon": true,never
"semicolon": true,always,ignore-interfaces
"semicolon": true,always,ignore-bound-class-methods
Schema
{
"type": "array",
"items": [
{
"type": "string",
"enum": [
"always",
"never"
]
},
{
"type": "string",
"enum": [
"ignore-interfaces"
]
}
],
"additionalItems": false
}
For more information see this page.
Missing semicolon Open
}
- Read upRead up
- Exclude checks
Rule: semicolon
Enforces consistent semicolon usage at the end of every statement.
Notes
- Has Fix
Config
One of the following arguments must be provided:
-
"always"
enforces semicolons at the end of every statement. -
"never"
disallows semicolons at the end of every statement except for when they are necessary.
The following arguments may be optionally provided:
-
"ignore-interfaces"
skips checking semicolons at the end of interface members. -
"ignore-bound-class-methods"
skips checking semicolons at the end of bound class methods. -
"strict-bound-class-methods"
disables any special handling of bound class methods and treats them as any other assignment. This option overrides"ignore-bound-class-methods"
.
Examples
"semicolon": true,always
"semicolon": true,never
"semicolon": true,always,ignore-interfaces
"semicolon": true,always,ignore-bound-class-methods
Schema
{
"type": "array",
"items": [
{
"type": "string",
"enum": [
"always",
"never"
]
},
{
"type": "string",
"enum": [
"ignore-interfaces"
]
}
],
"additionalItems": false
}
For more information see this page.
object access via string literals is disallowed Open
id = input['id'];
- Read upRead up
- Exclude checks
Rule: no-string-literal
Forbids unnecessary string literal property access.
Allows obj["prop-erty"]
(can't be a regular property access).
Disallows obj["property"]
(should be obj.property
).
Rationale
If --noImplicitAny
is turned off,
property access via a string literal will be 'any' if the property does not exist.
Notes
- Has Fix
Config
Not configurable.
Examples
"no-string-literal": true
For more information see this page.
Type assertion using the '<>' syntax is forbidden. Use the 'as' syntax instead. Open
return (decode) ? JSON.parse(<string>input) : JSON.stringify(<{[key: string]: any}>input)
- Read upRead up
- Exclude checks
Rule: no-angle-bracket-type-assertion
Requires the use of as Type
for type assertions instead of <Type>
.
Rationale
Both formats of type assertions have the same effect, but only as
type assertions
work in .tsx
files. This rule ensures that you have a consistent type assertion style
across your codebase.
Notes
- TypeScript Only
- Has Fix
Config
Not configurable.
Examples
"no-angle-bracket-type-assertion": true
For more information see this page.
Shadowed name: 'input' Open
read: (input: Input) => response({ message: 'Input params error' }, 400),
- Read upRead up
- Exclude checks
Rule: no-shadowed-variable
Disallows shadowing variable declarations.
Rationale
When a variable in a local scope and a variable in the containing scope have the same name, shadowing occurs. Shadowing makes it impossible to access the variable in the containing scope and obscures to what value an identifier actually refers. Compare the following snippets:
const a = 'no shadow';
function print() {
console.log(a);
}
print(); // logs 'no shadow'.
const a = 'no shadow';
function print() {
const a = 'shadow'; // TSLint will complain here.
console.log(a);
}
print(); // logs 'shadow'.
ESLint has an equivalent rule. For more background information, refer to this MDN closure doc.
Config
You can optionally pass an object to disable checking for certain kinds of declarations.
Possible keys are "class"
, "enum"
, "function"
, "import"
, "interface"
, "namespace"
, "typeAlias"
and "typeParameter"
. You can also pass "underscore
" to ignore variable names that begin with _
.
Just set the value to false
for the check you want to disable.
All checks default to true
, i.e. are enabled by default.
Note that you cannot disable variables and parameters.
The option "temporalDeadZone"
defaults to true
which shows errors when shadowing block scoped declarations in their
temporal dead zone. When set to false
parameters, classes, enums and variables declared
with let
or const
are not considered shadowed if the shadowing occurs within their
temporal dead zone.
The following example shows how the "temporalDeadZone"
option changes the linting result:
function fn(value) {
if (value) {
const tmp = value; // no error on this line if "temporalDeadZone" is false
return tmp;
}
let tmp = undefined;
if (!value) {
const tmp = value; // this line always contains an error
return tmp;
}
}
Examples
"no-shadowed-variable": true
"no-shadowed-variable": true,[object Object]
Schema
{
"type": "object",
"properties": {
"class": {
"type": "boolean"
},
"enum": {
"type": "boolean"
},
"function": {
"type": "boolean"
},
"import": {
"type": "boolean"
},
"interface": {
"type": "boolean"
},
"namespace": {
"type": "boolean"
},
"typeAlias": {
"type": "boolean"
},
"typeParameter": {
"type": "boolean"
},
"temporalDeadZone": {
"type": "boolean"
},
"underscore": {
"type": "boolean"
}
}
}
For more information see this page.
Shadowed name: 'input' Open
write: (input: Input) => response({ message: 'Input params error' }, 400),
- Read upRead up
- Exclude checks
Rule: no-shadowed-variable
Disallows shadowing variable declarations.
Rationale
When a variable in a local scope and a variable in the containing scope have the same name, shadowing occurs. Shadowing makes it impossible to access the variable in the containing scope and obscures to what value an identifier actually refers. Compare the following snippets:
const a = 'no shadow';
function print() {
console.log(a);
}
print(); // logs 'no shadow'.
const a = 'no shadow';
function print() {
const a = 'shadow'; // TSLint will complain here.
console.log(a);
}
print(); // logs 'shadow'.
ESLint has an equivalent rule. For more background information, refer to this MDN closure doc.
Config
You can optionally pass an object to disable checking for certain kinds of declarations.
Possible keys are "class"
, "enum"
, "function"
, "import"
, "interface"
, "namespace"
, "typeAlias"
and "typeParameter"
. You can also pass "underscore
" to ignore variable names that begin with _
.
Just set the value to false
for the check you want to disable.
All checks default to true
, i.e. are enabled by default.
Note that you cannot disable variables and parameters.
The option "temporalDeadZone"
defaults to true
which shows errors when shadowing block scoped declarations in their
temporal dead zone. When set to false
parameters, classes, enums and variables declared
with let
or const
are not considered shadowed if the shadowing occurs within their
temporal dead zone.
The following example shows how the "temporalDeadZone"
option changes the linting result:
function fn(value) {
if (value) {
const tmp = value; // no error on this line if "temporalDeadZone" is false
return tmp;
}
let tmp = undefined;
if (!value) {
const tmp = value; // this line always contains an error
return tmp;
}
}
Examples
"no-shadowed-variable": true
"no-shadowed-variable": true,[object Object]
Schema
{
"type": "object",
"properties": {
"class": {
"type": "boolean"
},
"enum": {
"type": "boolean"
},
"function": {
"type": "boolean"
},
"import": {
"type": "boolean"
},
"interface": {
"type": "boolean"
},
"namespace": {
"type": "boolean"
},
"typeAlias": {
"type": "boolean"
},
"typeParameter": {
"type": "boolean"
},
"temporalDeadZone": {
"type": "boolean"
},
"underscore": {
"type": "boolean"
}
}
}
For more information see this page.
Missing semicolon Open
})
- Read upRead up
- Exclude checks
Rule: semicolon
Enforces consistent semicolon usage at the end of every statement.
Notes
- Has Fix
Config
One of the following arguments must be provided:
-
"always"
enforces semicolons at the end of every statement. -
"never"
disallows semicolons at the end of every statement except for when they are necessary.
The following arguments may be optionally provided:
-
"ignore-interfaces"
skips checking semicolons at the end of interface members. -
"ignore-bound-class-methods"
skips checking semicolons at the end of bound class methods. -
"strict-bound-class-methods"
disables any special handling of bound class methods and treats them as any other assignment. This option overrides"ignore-bound-class-methods"
.
Examples
"semicolon": true,always
"semicolon": true,never
"semicolon": true,always,ignore-interfaces
"semicolon": true,always,ignore-bound-class-methods
Schema
{
"type": "array",
"items": [
{
"type": "string",
"enum": [
"always",
"never"
]
},
{
"type": "string",
"enum": [
"ignore-interfaces"
]
}
],
"additionalItems": false
}
For more information see this page.
Shadowed name: 'input' Open
write: (input: Input) => response({input: input, action: 'write'}, 200),
- Read upRead up
- Exclude checks
Rule: no-shadowed-variable
Disallows shadowing variable declarations.
Rationale
When a variable in a local scope and a variable in the containing scope have the same name, shadowing occurs. Shadowing makes it impossible to access the variable in the containing scope and obscures to what value an identifier actually refers. Compare the following snippets:
const a = 'no shadow';
function print() {
console.log(a);
}
print(); // logs 'no shadow'.
const a = 'no shadow';
function print() {
const a = 'shadow'; // TSLint will complain here.
console.log(a);
}
print(); // logs 'shadow'.
ESLint has an equivalent rule. For more background information, refer to this MDN closure doc.
Config
You can optionally pass an object to disable checking for certain kinds of declarations.
Possible keys are "class"
, "enum"
, "function"
, "import"
, "interface"
, "namespace"
, "typeAlias"
and "typeParameter"
. You can also pass "underscore
" to ignore variable names that begin with _
.
Just set the value to false
for the check you want to disable.
All checks default to true
, i.e. are enabled by default.
Note that you cannot disable variables and parameters.
The option "temporalDeadZone"
defaults to true
which shows errors when shadowing block scoped declarations in their
temporal dead zone. When set to false
parameters, classes, enums and variables declared
with let
or const
are not considered shadowed if the shadowing occurs within their
temporal dead zone.
The following example shows how the "temporalDeadZone"
option changes the linting result:
function fn(value) {
if (value) {
const tmp = value; // no error on this line if "temporalDeadZone" is false
return tmp;
}
let tmp = undefined;
if (!value) {
const tmp = value; // this line always contains an error
return tmp;
}
}
Examples
"no-shadowed-variable": true
"no-shadowed-variable": true,[object Object]
Schema
{
"type": "object",
"properties": {
"class": {
"type": "boolean"
},
"enum": {
"type": "boolean"
},
"function": {
"type": "boolean"
},
"import": {
"type": "boolean"
},
"interface": {
"type": "boolean"
},
"namespace": {
"type": "boolean"
},
"typeAlias": {
"type": "boolean"
},
"typeParameter": {
"type": "boolean"
},
"temporalDeadZone": {
"type": "boolean"
},
"underscore": {
"type": "boolean"
}
}
}
For more information see this page.
== should be === Open
'd': (function_name == 'read' && id !== false && action in ['d', 'del', 'rm', 'delete', 'remove', 'clear']),
- Read upRead up
- Exclude checks
Rule: triple-equals
Requires ===
and !==
in place of ==
and !=
.
Config
Two arguments may be optionally provided:
-
"allow-null-check"
allows==
and!=
when comparing tonull
. -
"allow-undefined-check"
allows==
and!=
when comparing toundefined
.
Examples
"triple-equals": true
"triple-equals": true,allow-null-check
"triple-equals": true,allow-undefined-check
Schema
{
"type": "array",
"items": {
"type": "string",
"enum": [
"allow-null-check",
"allow-undefined-check"
]
},
"minLength": 0,
"maxLength": 2
}
For more information see this page.
Unnecessary semicolon Open
};
- Read upRead up
- Exclude checks
Rule: semicolon
Enforces consistent semicolon usage at the end of every statement.
Notes
- Has Fix
Config
One of the following arguments must be provided:
-
"always"
enforces semicolons at the end of every statement. -
"never"
disallows semicolons at the end of every statement except for when they are necessary.
The following arguments may be optionally provided:
-
"ignore-interfaces"
skips checking semicolons at the end of interface members. -
"ignore-bound-class-methods"
skips checking semicolons at the end of bound class methods. -
"strict-bound-class-methods"
disables any special handling of bound class methods and treats them as any other assignment. This option overrides"ignore-bound-class-methods"
.
Examples
"semicolon": true,always
"semicolon": true,never
"semicolon": true,always,ignore-interfaces
"semicolon": true,always,ignore-bound-class-methods
Schema
{
"type": "array",
"items": [
{
"type": "string",
"enum": [
"always",
"never"
]
},
{
"type": "string",
"enum": [
"ignore-interfaces"
]
}
],
"additionalItems": false
}
For more information see this page.
Missing semicolon Open
console.log(method)
- Read upRead up
- Exclude checks
Rule: semicolon
Enforces consistent semicolon usage at the end of every statement.
Notes
- Has Fix
Config
One of the following arguments must be provided:
-
"always"
enforces semicolons at the end of every statement. -
"never"
disallows semicolons at the end of every statement except for when they are necessary.
The following arguments may be optionally provided:
-
"ignore-interfaces"
skips checking semicolons at the end of interface members. -
"ignore-bound-class-methods"
skips checking semicolons at the end of bound class methods. -
"strict-bound-class-methods"
disables any special handling of bound class methods and treats them as any other assignment. This option overrides"ignore-bound-class-methods"
.
Examples
"semicolon": true,always
"semicolon": true,never
"semicolon": true,always,ignore-interfaces
"semicolon": true,always,ignore-bound-class-methods
Schema
{
"type": "array",
"items": [
{
"type": "string",
"enum": [
"always",
"never"
]
},
{
"type": "string",
"enum": [
"ignore-interfaces"
]
}
],
"additionalItems": false
}
For more information see this page.
Missing semicolon Open
}
- Read upRead up
- Exclude checks
Rule: semicolon
Enforces consistent semicolon usage at the end of every statement.
Notes
- Has Fix
Config
One of the following arguments must be provided:
-
"always"
enforces semicolons at the end of every statement. -
"never"
disallows semicolons at the end of every statement except for when they are necessary.
The following arguments may be optionally provided:
-
"ignore-interfaces"
skips checking semicolons at the end of interface members. -
"ignore-bound-class-methods"
skips checking semicolons at the end of bound class methods. -
"strict-bound-class-methods"
disables any special handling of bound class methods and treats them as any other assignment. This option overrides"ignore-bound-class-methods"
.
Examples
"semicolon": true,always
"semicolon": true,never
"semicolon": true,always,ignore-interfaces
"semicolon": true,always,ignore-bound-class-methods
Schema
{
"type": "array",
"items": [
{
"type": "string",
"enum": [
"always",
"never"
]
},
{
"type": "string",
"enum": [
"ignore-interfaces"
]
}
],
"additionalItems": false
}
For more information see this page.
Shadowed name: 'input' Open
write: (input: Input) => response({ message: 'Not found' }, 404),
- Read upRead up
- Exclude checks
Rule: no-shadowed-variable
Disallows shadowing variable declarations.
Rationale
When a variable in a local scope and a variable in the containing scope have the same name, shadowing occurs. Shadowing makes it impossible to access the variable in the containing scope and obscures to what value an identifier actually refers. Compare the following snippets:
const a = 'no shadow';
function print() {
console.log(a);
}
print(); // logs 'no shadow'.
const a = 'no shadow';
function print() {
const a = 'shadow'; // TSLint will complain here.
console.log(a);
}
print(); // logs 'shadow'.
ESLint has an equivalent rule. For more background information, refer to this MDN closure doc.
Config
You can optionally pass an object to disable checking for certain kinds of declarations.
Possible keys are "class"
, "enum"
, "function"
, "import"
, "interface"
, "namespace"
, "typeAlias"
and "typeParameter"
. You can also pass "underscore
" to ignore variable names that begin with _
.
Just set the value to false
for the check you want to disable.
All checks default to true
, i.e. are enabled by default.
Note that you cannot disable variables and parameters.
The option "temporalDeadZone"
defaults to true
which shows errors when shadowing block scoped declarations in their
temporal dead zone. When set to false
parameters, classes, enums and variables declared
with let
or const
are not considered shadowed if the shadowing occurs within their
temporal dead zone.
The following example shows how the "temporalDeadZone"
option changes the linting result:
function fn(value) {
if (value) {
const tmp = value; // no error on this line if "temporalDeadZone" is false
return tmp;
}
let tmp = undefined;
if (!value) {
const tmp = value; // this line always contains an error
return tmp;
}
}
Examples
"no-shadowed-variable": true
"no-shadowed-variable": true,[object Object]
Schema
{
"type": "object",
"properties": {
"class": {
"type": "boolean"
},
"enum": {
"type": "boolean"
},
"function": {
"type": "boolean"
},
"import": {
"type": "boolean"
},
"interface": {
"type": "boolean"
},
"namespace": {
"type": "boolean"
},
"typeAlias": {
"type": "boolean"
},
"typeParameter": {
"type": "boolean"
},
"temporalDeadZone": {
"type": "boolean"
},
"underscore": {
"type": "boolean"
}
}
}
For more information see this page.
Shadowed name: 'input' Open
write: (input: Input) => response({ message: 'Not found' }, 404),
- Read upRead up
- Exclude checks
Rule: no-shadowed-variable
Disallows shadowing variable declarations.
Rationale
When a variable in a local scope and a variable in the containing scope have the same name, shadowing occurs. Shadowing makes it impossible to access the variable in the containing scope and obscures to what value an identifier actually refers. Compare the following snippets:
const a = 'no shadow';
function print() {
console.log(a);
}
print(); // logs 'no shadow'.
const a = 'no shadow';
function print() {
const a = 'shadow'; // TSLint will complain here.
console.log(a);
}
print(); // logs 'shadow'.
ESLint has an equivalent rule. For more background information, refer to this MDN closure doc.
Config
You can optionally pass an object to disable checking for certain kinds of declarations.
Possible keys are "class"
, "enum"
, "function"
, "import"
, "interface"
, "namespace"
, "typeAlias"
and "typeParameter"
. You can also pass "underscore
" to ignore variable names that begin with _
.
Just set the value to false
for the check you want to disable.
All checks default to true
, i.e. are enabled by default.
Note that you cannot disable variables and parameters.
The option "temporalDeadZone"
defaults to true
which shows errors when shadowing block scoped declarations in their
temporal dead zone. When set to false
parameters, classes, enums and variables declared
with let
or const
are not considered shadowed if the shadowing occurs within their
temporal dead zone.
The following example shows how the "temporalDeadZone"
option changes the linting result:
function fn(value) {
if (value) {
const tmp = value; // no error on this line if "temporalDeadZone" is false
return tmp;
}
let tmp = undefined;
if (!value) {
const tmp = value; // this line always contains an error
return tmp;
}
}
Examples
"no-shadowed-variable": true
"no-shadowed-variable": true,[object Object]
Schema
{
"type": "object",
"properties": {
"class": {
"type": "boolean"
},
"enum": {
"type": "boolean"
},
"function": {
"type": "boolean"
},
"import": {
"type": "boolean"
},
"interface": {
"type": "boolean"
},
"namespace": {
"type": "boolean"
},
"typeAlias": {
"type": "boolean"
},
"typeParameter": {
"type": "boolean"
},
"temporalDeadZone": {
"type": "boolean"
},
"underscore": {
"type": "boolean"
}
}
}
For more information see this page.
object access via string literals is disallowed Open
delete input['id'];
- Read upRead up
- Exclude checks
Rule: no-string-literal
Forbids unnecessary string literal property access.
Allows obj["prop-erty"]
(can't be a regular property access).
Disallows obj["property"]
(should be obj.property
).
Rationale
If --noImplicitAny
is turned off,
property access via a string literal will be 'any' if the property does not exist.
Notes
- Has Fix
Config
Not configurable.
Examples
"no-string-literal": true
For more information see this page.
Missing semicolon Open
body: Body
- Read upRead up
- Exclude checks
Rule: semicolon
Enforces consistent semicolon usage at the end of every statement.
Notes
- Has Fix
Config
One of the following arguments must be provided:
-
"always"
enforces semicolons at the end of every statement. -
"never"
disallows semicolons at the end of every statement except for when they are necessary.
The following arguments may be optionally provided:
-
"ignore-interfaces"
skips checking semicolons at the end of interface members. -
"ignore-bound-class-methods"
skips checking semicolons at the end of bound class methods. -
"strict-bound-class-methods"
disables any special handling of bound class methods and treats them as any other assignment. This option overrides"ignore-bound-class-methods"
.
Examples
"semicolon": true,always
"semicolon": true,never
"semicolon": true,always,ignore-interfaces
"semicolon": true,always,ignore-bound-class-methods
Schema
{
"type": "array",
"items": [
{
"type": "string",
"enum": [
"always",
"never"
]
},
{
"type": "string",
"enum": [
"ignore-interfaces"
]
}
],
"additionalItems": false
}
For more information see this page.
Array type using 'Array<t>' is forbidden. Use 'T[]' instead.</t> Open
export const QUERY_METHODS: Array<QueryMethod> = ['GET', 'DELETE', 'OPTION'];
- Read upRead up
- Exclude checks
Rule: array-type
Requires using either 'T[]' or 'Array<t>' for arrays.</t>
Notes
- TypeScript Only
- Has Fix
Config
One of the following arguments must be provided:
-
"array"
enforces use ofT[]
for all types T. -
"generic"
enforces use ofArray<T>
for all types T. -
"array-simple"
enforces use ofT[]
ifT
is a simple type (primitive or type reference).
Examples
"array-type": true,array
"array-type": true,generic
"array-type": true,array-simple
Schema
{
"type": "string",
"enum": [
"array",
"generic",
"array-simple"
]
}
For more information see this page.
Shadowed name: 'input' Open
read: (input: Input) => response({input: input, action: 'read'}, 200),
- Read upRead up
- Exclude checks
Rule: no-shadowed-variable
Disallows shadowing variable declarations.
Rationale
When a variable in a local scope and a variable in the containing scope have the same name, shadowing occurs. Shadowing makes it impossible to access the variable in the containing scope and obscures to what value an identifier actually refers. Compare the following snippets:
const a = 'no shadow';
function print() {
console.log(a);
}
print(); // logs 'no shadow'.
const a = 'no shadow';
function print() {
const a = 'shadow'; // TSLint will complain here.
console.log(a);
}
print(); // logs 'shadow'.
ESLint has an equivalent rule. For more background information, refer to this MDN closure doc.
Config
You can optionally pass an object to disable checking for certain kinds of declarations.
Possible keys are "class"
, "enum"
, "function"
, "import"
, "interface"
, "namespace"
, "typeAlias"
and "typeParameter"
. You can also pass "underscore
" to ignore variable names that begin with _
.
Just set the value to false
for the check you want to disable.
All checks default to true
, i.e. are enabled by default.
Note that you cannot disable variables and parameters.
The option "temporalDeadZone"
defaults to true
which shows errors when shadowing block scoped declarations in their
temporal dead zone. When set to false
parameters, classes, enums and variables declared
with let
or const
are not considered shadowed if the shadowing occurs within their
temporal dead zone.
The following example shows how the "temporalDeadZone"
option changes the linting result:
function fn(value) {
if (value) {
const tmp = value; // no error on this line if "temporalDeadZone" is false
return tmp;
}
let tmp = undefined;
if (!value) {
const tmp = value; // this line always contains an error
return tmp;
}
}
Examples
"no-shadowed-variable": true
"no-shadowed-variable": true,[object Object]
Schema
{
"type": "object",
"properties": {
"class": {
"type": "boolean"
},
"enum": {
"type": "boolean"
},
"function": {
"type": "boolean"
},
"import": {
"type": "boolean"
},
"interface": {
"type": "boolean"
},
"namespace": {
"type": "boolean"
},
"typeAlias": {
"type": "boolean"
},
"typeParameter": {
"type": "boolean"
},
"temporalDeadZone": {
"type": "boolean"
},
"underscore": {
"type": "boolean"
}
}
}
For more information see this page.
Shadowed name: 'input' Open
read: (input: Input) => response({ message: 'Not found' }, 404),
- Read upRead up
- Exclude checks
Rule: no-shadowed-variable
Disallows shadowing variable declarations.
Rationale
When a variable in a local scope and a variable in the containing scope have the same name, shadowing occurs. Shadowing makes it impossible to access the variable in the containing scope and obscures to what value an identifier actually refers. Compare the following snippets:
const a = 'no shadow';
function print() {
console.log(a);
}
print(); // logs 'no shadow'.
const a = 'no shadow';
function print() {
const a = 'shadow'; // TSLint will complain here.
console.log(a);
}
print(); // logs 'shadow'.
ESLint has an equivalent rule. For more background information, refer to this MDN closure doc.
Config
You can optionally pass an object to disable checking for certain kinds of declarations.
Possible keys are "class"
, "enum"
, "function"
, "import"
, "interface"
, "namespace"
, "typeAlias"
and "typeParameter"
. You can also pass "underscore
" to ignore variable names that begin with _
.
Just set the value to false
for the check you want to disable.
All checks default to true
, i.e. are enabled by default.
Note that you cannot disable variables and parameters.
The option "temporalDeadZone"
defaults to true
which shows errors when shadowing block scoped declarations in their
temporal dead zone. When set to false
parameters, classes, enums and variables declared
with let
or const
are not considered shadowed if the shadowing occurs within their
temporal dead zone.
The following example shows how the "temporalDeadZone"
option changes the linting result:
function fn(value) {
if (value) {
const tmp = value; // no error on this line if "temporalDeadZone" is false
return tmp;
}
let tmp = undefined;
if (!value) {
const tmp = value; // this line always contains an error
return tmp;
}
}
Examples
"no-shadowed-variable": true
"no-shadowed-variable": true,[object Object]
Schema
{
"type": "object",
"properties": {
"class": {
"type": "boolean"
},
"enum": {
"type": "boolean"
},
"function": {
"type": "boolean"
},
"import": {
"type": "boolean"
},
"interface": {
"type": "boolean"
},
"namespace": {
"type": "boolean"
},
"typeAlias": {
"type": "boolean"
},
"typeParameter": {
"type": "boolean"
},
"temporalDeadZone": {
"type": "boolean"
},
"underscore": {
"type": "boolean"
}
}
}
For more information see this page.
object access via string literals is disallowed Open
const message = 'message' in data ? data['message']: 'Internal Server Error';
- Read upRead up
- Exclude checks
Rule: no-string-literal
Forbids unnecessary string literal property access.
Allows obj["prop-erty"]
(can't be a regular property access).
Disallows obj["property"]
(should be obj.property
).
Rationale
If --noImplicitAny
is turned off,
property access via a string literal will be 'any' if the property does not exist.
Notes
- Has Fix
Config
Not configurable.
Examples
"no-string-literal": true
For more information see this page.
Expected property shorthand in object literal ('{input}'). Open
input: input,
- Read upRead up
- Exclude checks
Rule: object-literal-shorthand
Enforces/disallows use of ES6 object literal shorthand.
Notes
- Has Fix
Config
"always"
assumed to be default option, thus with no options provided
the rule enforces object literal methods and properties shorthands.
With "never"
option provided, any shorthand object literal syntax causes an error.
The rule can be configured in a more granular way.
With {"property": "never"}
provided (which is equivalent to {"property": "never", "method": "always"}
),
the rule only flags property shorthand assignments,
and respectively with {"method": "never"}
(equivalent to {"property": "always", "method": "never"}
),
the rule fails only on method shorthands.
Examples
"object-literal-shorthand": true
"object-literal-shorthand": true,never
"object-literal-shorthand": true,[object Object]
Schema
{
"oneOf": [
{
"type": "string",
"enum": [
"never"
]
},
{
"type": "object",
"properties": {
"property": {
"type": "string",
"enum": [
"never"
]
},
"method": {
"type": "string",
"enum": [
"never"
]
}
},
"minProperties": 1,
"maxProperties": 2
}
]
}
For more information see this page.
Type assertion on object literals is forbidden, use a type annotation instead. Open
return JSON.stringify(<Data>{
code: decode ? 400 : 500,
status: 'error',
message: 'Invalid JSON'
});
- Read upRead up
- Exclude checks
Rule: no-object-literal-type-assertion
Forbids an object literal to appear in a type assertion expression.
Casting to any
or to unknown
is still allowed.
Rationale
Always prefer const x: T = { ... };
to const x = { ... } as T;
.
The type assertion in the latter case is either unnecessary or hides an error.
The compiler will warn for excess properties with this syntax, but not missing required fields.
For example: const x: { foo: number } = {}
will fail to compile, but
const x = {} as { foo: number }
will succeed.
Additionally, the const assertion const x = { foo: 1 } as const
,
introduced in TypeScript 3.4, is considered beneficial and is ignored by this rule.
Notes
- TypeScript Only
Config
One option may be configured:
-
allow-arguments
allows type assertions to be used on object literals inside call expressions.
Examples
"no-object-literal-type-assertion": true
"no-object-literal-type-assertion": true,[object Object]
Schema
{
"type": "object",
"properties": {
"allow-arguments": {
"type": "boolean"
}
},
"additionalProperties": false
}
For more information see this page.
Missing semicolon Open
}
- Read upRead up
- Exclude checks
Rule: semicolon
Enforces consistent semicolon usage at the end of every statement.
Notes
- Has Fix
Config
One of the following arguments must be provided:
-
"always"
enforces semicolons at the end of every statement. -
"never"
disallows semicolons at the end of every statement except for when they are necessary.
The following arguments may be optionally provided:
-
"ignore-interfaces"
skips checking semicolons at the end of interface members. -
"ignore-bound-class-methods"
skips checking semicolons at the end of bound class methods. -
"strict-bound-class-methods"
disables any special handling of bound class methods and treats them as any other assignment. This option overrides"ignore-bound-class-methods"
.
Examples
"semicolon": true,always
"semicolon": true,never
"semicolon": true,always,ignore-interfaces
"semicolon": true,always,ignore-bound-class-methods
Schema
{
"type": "array",
"items": [
{
"type": "string",
"enum": [
"always",
"never"
]
},
{
"type": "string",
"enum": [
"ignore-interfaces"
]
}
],
"additionalItems": false
}
For more information see this page.
Shadowed name: 'input' Open
read: (input: Input) => response({ message: 'Internal Server Error' }, 500),
- Read upRead up
- Exclude checks
Rule: no-shadowed-variable
Disallows shadowing variable declarations.
Rationale
When a variable in a local scope and a variable in the containing scope have the same name, shadowing occurs. Shadowing makes it impossible to access the variable in the containing scope and obscures to what value an identifier actually refers. Compare the following snippets:
const a = 'no shadow';
function print() {
console.log(a);
}
print(); // logs 'no shadow'.
const a = 'no shadow';
function print() {
const a = 'shadow'; // TSLint will complain here.
console.log(a);
}
print(); // logs 'shadow'.
ESLint has an equivalent rule. For more background information, refer to this MDN closure doc.
Config
You can optionally pass an object to disable checking for certain kinds of declarations.
Possible keys are "class"
, "enum"
, "function"
, "import"
, "interface"
, "namespace"
, "typeAlias"
and "typeParameter"
. You can also pass "underscore
" to ignore variable names that begin with _
.
Just set the value to false
for the check you want to disable.
All checks default to true
, i.e. are enabled by default.
Note that you cannot disable variables and parameters.
The option "temporalDeadZone"
defaults to true
which shows errors when shadowing block scoped declarations in their
temporal dead zone. When set to false
parameters, classes, enums and variables declared
with let
or const
are not considered shadowed if the shadowing occurs within their
temporal dead zone.
The following example shows how the "temporalDeadZone"
option changes the linting result:
function fn(value) {
if (value) {
const tmp = value; // no error on this line if "temporalDeadZone" is false
return tmp;
}
let tmp = undefined;
if (!value) {
const tmp = value; // this line always contains an error
return tmp;
}
}
Examples
"no-shadowed-variable": true
"no-shadowed-variable": true,[object Object]
Schema
{
"type": "object",
"properties": {
"class": {
"type": "boolean"
},
"enum": {
"type": "boolean"
},
"function": {
"type": "boolean"
},
"import": {
"type": "boolean"
},
"interface": {
"type": "boolean"
},
"namespace": {
"type": "boolean"
},
"typeAlias": {
"type": "boolean"
},
"typeParameter": {
"type": "boolean"
},
"temporalDeadZone": {
"type": "boolean"
},
"underscore": {
"type": "boolean"
}
}
}
For more information see this page.
object access via string literals is disallowed Open
delete data['message'];
- Read upRead up
- Exclude checks
Rule: no-string-literal
Forbids unnecessary string literal property access.
Allows obj["prop-erty"]
(can't be a regular property access).
Disallows obj["property"]
(should be obj.property
).
Rationale
If --noImplicitAny
is turned off,
property access via a string literal will be 'any' if the property does not exist.
Notes
- Has Fix
Config
Not configurable.
Examples
"no-string-literal": true
For more information see this page.
== should be === Open
'u': (function_name == 'write' && id !== false && action in ['default', 'u', 'update', 'upd']),
- Read upRead up
- Exclude checks
Rule: triple-equals
Requires ===
and !==
in place of ==
and !=
.
Config
Two arguments may be optionally provided:
-
"allow-null-check"
allows==
and!=
when comparing tonull
. -
"allow-undefined-check"
allows==
and!=
when comparing toundefined
.
Examples
"triple-equals": true
"triple-equals": true,allow-null-check
"triple-equals": true,allow-undefined-check
Schema
{
"type": "array",
"items": {
"type": "string",
"enum": [
"allow-null-check",
"allow-undefined-check"
]
},
"minLength": 0,
"maxLength": 2
}
For more information see this page.
Type assertion on object literals is forbidden, use a type annotation instead. Open
return await Promise.resolve(<Data>{
code: http_code,
status: (http_code >= 200 && http_code < 400) ? 'ok' : 'error',
message: (http_code >= 200 && http_code < 400) ? 'success' : message,
data: !!data ? data : null
- Read upRead up
- Exclude checks
Rule: no-object-literal-type-assertion
Forbids an object literal to appear in a type assertion expression.
Casting to any
or to unknown
is still allowed.
Rationale
Always prefer const x: T = { ... };
to const x = { ... } as T;
.
The type assertion in the latter case is either unnecessary or hides an error.
The compiler will warn for excess properties with this syntax, but not missing required fields.
For example: const x: { foo: number } = {}
will fail to compile, but
const x = {} as { foo: number }
will succeed.
Additionally, the const assertion const x = { foo: 1 } as const
,
introduced in TypeScript 3.4, is considered beneficial and is ignored by this rule.
Notes
- TypeScript Only
Config
One option may be configured:
-
allow-arguments
allows type assertions to be used on object literals inside call expressions.
Examples
"no-object-literal-type-assertion": true
"no-object-literal-type-assertion": true,[object Object]
Schema
{
"type": "object",
"properties": {
"allow-arguments": {
"type": "boolean"
}
},
"additionalProperties": false
}
For more information see this page.
missing whitespace Open
const body = "";//await parseBody(req);
- Read upRead up
- Exclude checks
Rule: whitespace
Enforces whitespace style conventions.
Rationale
Helps maintain a readable, consistent style in your codebase.
Notes
- Has Fix
Config
Several arguments may be optionally provided:
-
"check-branch"
checks branching statements (if
/else
/for
/while
) are followed by whitespace. -
"check-decl"
checks that variable declarations have whitespace around the equals token. -
"check-operator"
checks for whitespace around operator tokens. -
"check-module"
checks for whitespace in import & export statements. -
"check-separator"
checks for whitespace after separator tokens (,
/;
). -
"check-rest-spread"
checks that there is no whitespace after rest/spread operator (...
). -
"check-type"
checks for whitespace before a variable type specification. -
"check-typecast"
checks for whitespace between a typecast and its target. -
"check-type-operator"
checks for whitespace between type operators|
and&
. -
"check-preblock"
checks for whitespace before the opening brace of a block. -
"check-postbrace"
checks for whitespace after an opening brace.
Examples
"whitespace": true,check-branch,check-operator,check-typecast
Schema
{
"type": "array",
"items": {
"type": "string",
"enum": [
"check-branch",
"check-decl",
"check-operator",
"check-module",
"check-separator",
"check-rest-spread",
"check-type",
"check-typecast",
"check-type-operator",
"check-preblock",
"check-postbrace"
]
},
"minLength": 0,
"maxLength": 11
}
For more information see this page.
Missing semicolon Open
export type Input = { [key: string]: Input | string | number }
- Read upRead up
- Exclude checks
Rule: semicolon
Enforces consistent semicolon usage at the end of every statement.
Notes
- Has Fix
Config
One of the following arguments must be provided:
-
"always"
enforces semicolons at the end of every statement. -
"never"
disallows semicolons at the end of every statement except for when they are necessary.
The following arguments may be optionally provided:
-
"ignore-interfaces"
skips checking semicolons at the end of interface members. -
"ignore-bound-class-methods"
skips checking semicolons at the end of bound class methods. -
"strict-bound-class-methods"
disables any special handling of bound class methods and treats them as any other assignment. This option overrides"ignore-bound-class-methods"
.
Examples
"semicolon": true,always
"semicolon": true,never
"semicolon": true,always,ignore-interfaces
"semicolon": true,always,ignore-bound-class-methods
Schema
{
"type": "array",
"items": [
{
"type": "string",
"enum": [
"always",
"never"
]
},
{
"type": "string",
"enum": [
"ignore-interfaces"
]
}
],
"additionalItems": false
}
For more information see this page.
Missing semicolon Open
}
- Read upRead up
- Exclude checks
Rule: semicolon
Enforces consistent semicolon usage at the end of every statement.
Notes
- Has Fix
Config
One of the following arguments must be provided:
-
"always"
enforces semicolons at the end of every statement. -
"never"
disallows semicolons at the end of every statement except for when they are necessary.
The following arguments may be optionally provided:
-
"ignore-interfaces"
skips checking semicolons at the end of interface members. -
"ignore-bound-class-methods"
skips checking semicolons at the end of bound class methods. -
"strict-bound-class-methods"
disables any special handling of bound class methods and treats them as any other assignment. This option overrides"ignore-bound-class-methods"
.
Examples
"semicolon": true,always
"semicolon": true,never
"semicolon": true,always,ignore-interfaces
"semicolon": true,always,ignore-bound-class-methods
Schema
{
"type": "array",
"items": [
{
"type": "string",
"enum": [
"always",
"never"
]
},
{
"type": "string",
"enum": [
"ignore-interfaces"
]
}
],
"additionalItems": false
}
For more information see this page.
comment must start with a space Open
const body = "";//await parseBody(req);
- Read upRead up
- Exclude checks
Rule: comment-format
Enforces formatting rules for single-line comments.
Rationale
Helps maintain a consistent, readable style in your codebase.
Notes
- Has Fix
Config
Four arguments may be optionally provided:
-
"check-space"
requires that all single-line comments must begin with a space, as in// comment
- note that for comments starting with multiple slashes, e.g.
///
, leading slashes are ignored - TypeScript reference comments are ignored completely
- note that for comments starting with multiple slashes, e.g.
-
"check-lowercase"
requires that the first non-whitespace character of a comment must be lowercase, if applicable. -
"check-uppercase"
requires that the first non-whitespace character of a comment must be uppercase, if applicable. -
"allow-trailing-lowercase"
allows that only the first comment of a series of comments needs to be uppercase.- requires
"check-uppercase"
- comments must start at the same position
- requires
Exceptions to "check-lowercase"
or "check-uppercase"
can be managed with object that may be passed as last
argument.
One of two options can be provided in this object:
-
"ignore-words"
- array of strings - words that will be ignored at the beginning of the comment. -
"ignore-pattern"
- string - RegExp pattern that will be ignored at the beginning of the comment.
Examples
"comment-format": true,check-space,check-uppercase,allow-trailing-lowercase
"comment-format": true,check-lowercase,[object Object]
"comment-format": true,check-lowercase,[object Object]
Schema
{
"type": "array",
"items": {
"anyOf": [
{
"type": "string",
"enum": [
"check-space",
"check-lowercase",
"check-uppercase",
"allow-trailing-lowercase"
]
},
{
"type": "object",
"properties": {
"ignore-words": {
"type": "array",
"items": {
"type": "string"
}
},
"ignore-pattern": {
"type": "string"
}
},
"minProperties": 1,
"maxProperties": 1
}
]
},
"minLength": 1,
"maxLength": 5
}
For more information see this page.
Shadowed name: 'input' Open
read: (input: Input) => response({ message: 'Not found' }, 404),
- Read upRead up
- Exclude checks
Rule: no-shadowed-variable
Disallows shadowing variable declarations.
Rationale
When a variable in a local scope and a variable in the containing scope have the same name, shadowing occurs. Shadowing makes it impossible to access the variable in the containing scope and obscures to what value an identifier actually refers. Compare the following snippets:
const a = 'no shadow';
function print() {
console.log(a);
}
print(); // logs 'no shadow'.
const a = 'no shadow';
function print() {
const a = 'shadow'; // TSLint will complain here.
console.log(a);
}
print(); // logs 'shadow'.
ESLint has an equivalent rule. For more background information, refer to this MDN closure doc.
Config
You can optionally pass an object to disable checking for certain kinds of declarations.
Possible keys are "class"
, "enum"
, "function"
, "import"
, "interface"
, "namespace"
, "typeAlias"
and "typeParameter"
. You can also pass "underscore
" to ignore variable names that begin with _
.
Just set the value to false
for the check you want to disable.
All checks default to true
, i.e. are enabled by default.
Note that you cannot disable variables and parameters.
The option "temporalDeadZone"
defaults to true
which shows errors when shadowing block scoped declarations in their
temporal dead zone. When set to false
parameters, classes, enums and variables declared
with let
or const
are not considered shadowed if the shadowing occurs within their
temporal dead zone.
The following example shows how the "temporalDeadZone"
option changes the linting result:
function fn(value) {
if (value) {
const tmp = value; // no error on this line if "temporalDeadZone" is false
return tmp;
}
let tmp = undefined;
if (!value) {
const tmp = value; // this line always contains an error
return tmp;
}
}
Examples
"no-shadowed-variable": true
"no-shadowed-variable": true,[object Object]
Schema
{
"type": "object",
"properties": {
"class": {
"type": "boolean"
},
"enum": {
"type": "boolean"
},
"function": {
"type": "boolean"
},
"import": {
"type": "boolean"
},
"interface": {
"type": "boolean"
},
"namespace": {
"type": "boolean"
},
"typeAlias": {
"type": "boolean"
},
"typeParameter": {
"type": "boolean"
},
"temporalDeadZone": {
"type": "boolean"
},
"underscore": {
"type": "boolean"
}
}
}
For more information see this page.
Missing semicolon Open
}
- Read upRead up
- Exclude checks
Rule: semicolon
Enforces consistent semicolon usage at the end of every statement.
Notes
- Has Fix
Config
One of the following arguments must be provided:
-
"always"
enforces semicolons at the end of every statement. -
"never"
disallows semicolons at the end of every statement except for when they are necessary.
The following arguments may be optionally provided:
-
"ignore-interfaces"
skips checking semicolons at the end of interface members. -
"ignore-bound-class-methods"
skips checking semicolons at the end of bound class methods. -
"strict-bound-class-methods"
disables any special handling of bound class methods and treats them as any other assignment. This option overrides"ignore-bound-class-methods"
.
Examples
"semicolon": true,always
"semicolon": true,never
"semicolon": true,always,ignore-interfaces
"semicolon": true,always,ignore-bound-class-methods
Schema
{
"type": "array",
"items": [
{
"type": "string",
"enum": [
"always",
"never"
]
},
{
"type": "string",
"enum": [
"ignore-interfaces"
]
}
],
"additionalItems": false
}
For more information see this page.