Showing 82 of 82 total issues
Missing semicolon Open
}
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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'];
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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),
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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.
Unnecessary 'await'. Open
return await response({
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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.
Missing semicolon Open
})
- Read upRead up
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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.
Expected property shorthand in object literal ('{input}'). Open
read: (input: Input) => response({input: input, action: 'read'}, 200),
- Read upRead up
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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.
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.
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)
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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);
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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']),
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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>{
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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.
object access via string literals is disallowed Open
[Action.READ]: [200, { ...model, id: input['id'], name: `Chat #${input['id']}` }],
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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.
Multiple imports from './io' can be combined into one. Open
import { Route, Data, IncomingMessage, ServerResponse } from './io';
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Rule: no-duplicate-imports
Disallows multiple import statements from the same module.
Rationale
Using a single import statement per module will make the code clearer because you can see everything being imported from that module on one line.
Config
"allow-namespace-imports" allows you to import namespaces on separate lines.
Examples
"no-duplicate-imports": true,[object Object]
Schema
{
"type": "object",
"properties": {
"allow-namespace-imports": {
"type": "boolean"
}
}
}
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'];
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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.