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 50.

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

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 47.

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

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 47.

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

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 47.

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

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 47.

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

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 40.

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

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 40.

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

Rule: no-inferrable-types

Disallows explicit type declarations for variables or parameters initialized to a number, string, or boolean.

Rationale

Explicit types where they can be easily inferred by the compiler make code more verbose.

Notes

• TypeScript Only
• Has Fix

Config

Two arguments may be optionally provided:

• ignore-params allows specifying an inferrable type annotation for function params. This can be useful when combining with the typedef rule.
• ignore-properties allows specifying an inferrable type annotation for class properties.

Examples

"no-inferrable-types": true

"no-inferrable-types": true,ignore-params

"no-inferrable-types": true,ignore-params,ignore-properties

Schema

{
  "type": "array",
  "items": {
    "type": "string",
    "enum": [
      "ignore-params",
      "ignore-properties"
    ]
  },
  "minLength": 0,
  "maxLength": 2
}

For more information see this page.

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.

Rule: no-inferrable-types

Disallows explicit type declarations for variables or parameters initialized to a number, string, or boolean.

Rationale

Explicit types where they can be easily inferred by the compiler make code more verbose.

Notes

• TypeScript Only
• Has Fix

Config

Two arguments may be optionally provided:

• ignore-params allows specifying an inferrable type annotation for function params. This can be useful when combining with the typedef rule.
• ignore-properties allows specifying an inferrable type annotation for class properties.

Examples

"no-inferrable-types": true

"no-inferrable-types": true,ignore-params

"no-inferrable-types": true,ignore-params,ignore-properties

Schema

{
  "type": "array",
  "items": {
    "type": "string",
    "enum": [
      "ignore-params",
      "ignore-properties"
    ]
  },
  "minLength": 0,
  "maxLength": 2
}

For more information see this page.

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.

Rule: component-selector

Component selectors should follow given naming rules.

See more at https://angular.io/guide/styleguide#style-02-07, https://angular.io/guide/styleguide#style-05-02 and https://angular.io/guide/styleguide#style-05-03.

Rationale

• Consistent conventions make it easy to quickly identify and reference assets of different types.
• Makes it easier to promote and share the component in other apps.
• Components are easy to identify in the DOM.
• Keeps the element names consistent with the specification for Custom Elements.
• Components have templates containing HTML and optional Angular template syntax.
• They display content. Developers place components on the page as they would native HTML elements and WebComponents.
• It is easier to recognize that a symbol is a component by looking at the template's HTML.

Notes

• TypeScript Only

Config

Options accept three obligatory items as an array: 1. element or attribute forces components to be used as either elements, attributes, or both (not recommended) 2. A single prefix (string) or array of prefixes (strings) which have to be used in component selectors. 3. kebab-case or camelCase allows you to pick a case.

Examples

"component-selector": true,element,my-prefix,kebab-case

"component-selector": true,element,ng,ngx,kebab-case

"component-selector": true,attribute,myPrefix,camelCase

"component-selector": true,element,attribute,myPrefix,camelCase

Schema

{
  "items": [
    {
      "enum": [
        "attribute",
        "element"
      ]
    },
    {
      "oneOf": [
        {
          "items": {
            "type": "string"
          },
          "type": "array"
        },
        {
          "type": "string"
        }
      ]
    },
    {
      "enum": [
        "camelCase",
        "kebab-case"
      ]
    }
  ],
  "maxLength": 3,
  "minLength": 3,
  "type": "array"
}

For more information see this page.

Rule: radix

Requires the radix parameter to be specified when calling parseInt.

Rationale

From MDN:

Always specify this parameter to eliminate reader confusion and to guarantee predictable behavior. Different implementations produce different results when a radix is not specified, usually defaulting the value to 10.

Config

Not configurable.

Examples

"radix": true

For more information see this page.

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.

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.

Rule: component-selector

Component selectors should follow given naming rules.

See more at https://angular.io/guide/styleguide#style-02-07, https://angular.io/guide/styleguide#style-05-02 and https://angular.io/guide/styleguide#style-05-03.

Rationale

• Consistent conventions make it easy to quickly identify and reference assets of different types.
• Makes it easier to promote and share the component in other apps.
• Components are easy to identify in the DOM.
• Keeps the element names consistent with the specification for Custom Elements.
• Components have templates containing HTML and optional Angular template syntax.
• They display content. Developers place components on the page as they would native HTML elements and WebComponents.
• It is easier to recognize that a symbol is a component by looking at the template's HTML.

Notes

• TypeScript Only

Config

Options accept three obligatory items as an array: 1. element or attribute forces components to be used as either elements, attributes, or both (not recommended) 2. A single prefix (string) or array of prefixes (strings) which have to be used in component selectors. 3. kebab-case or camelCase allows you to pick a case.

Examples

"component-selector": true,element,my-prefix,kebab-case

"component-selector": true,element,ng,ngx,kebab-case

"component-selector": true,attribute,myPrefix,camelCase

"component-selector": true,element,attribute,myPrefix,camelCase

Schema

{
  "items": [
    {
      "enum": [
        "attribute",
        "element"
      ]
    },
    {
      "oneOf": [
        {
          "items": {
            "type": "string"
          },
          "type": "array"
        },
        {
          "type": "string"
        }
      ]
    },
    {
      "enum": [
        "camelCase",
        "kebab-case"
      ]
    }
  ],
  "maxLength": 3,
  "minLength": 3,
  "type": "array"
}

For more information see this page.