For more information visit Source: http://eslint.org/docs/rules/

enforce the consistent use of either backticks, double, or single quotes (quotes)

JavaScript allows you to define strings in one of three ways: double quotes, single quotes, and backticks (as of ECMAScript 6). For example:

/*eslint-env es6*/

var double = "double";
var single = 'single';
var backtick = `backtick`;    // ES6 only

Each of these lines creates a string and, in some cases, can be used interchangeably. The choice of how to define strings in a codebase is a stylistic one outside of template literals (which allow embedded of expressions to be interpreted).

Many codebases require strings to be defined in a consistent manner.

Rule Details

This rule enforces the consistent use of either backticks, double, or single quotes.

Options

This rule has two options, a string option and an object option.

String option:

• "double" (default) requires the use of double quotes wherever possible
• "single" requires the use of single quotes wherever possible
• "backtick" requires the use of backticks wherever possible

Object option:

• "avoidEscape": true allows strings to use single-quotes or double-quotes so long as the string contains a quote that would have to be escaped otherwise
• "allowTemplateLiterals": true allows strings to use backticks

Deprecated: The object property avoid-escape is deprecated; please use the object property avoidEscape instead.

double

Examples of incorrect code for this rule with the default "double" option:

/*eslint quotes: ["error", "double"]*/

var single = 'single';
var unescaped = 'a string containing "double" quotes';
var backtick = `back\ntick`; // you can use \n in single or double quoted strings

Examples of correct code for this rule with the default "double" option:

/*eslint quotes: ["error", "double"]*/
/*eslint-env es6*/

var double = "double";
var backtick = `back
tick`;  // backticks are allowed due to newline
var backtick = tag`backtick`; // backticks are allowed due to tag

single

Examples of incorrect code for this rule with the "single" option:

/*eslint quotes: ["error", "single"]*/

var double = "double";
var unescaped = "a string containing 'single' quotes";

Examples of correct code for this rule with the "single" option:

/*eslint quotes: ["error", "single"]*/
/*eslint-env es6*/

var single = 'single';
var backtick = `back${x}tick`; // backticks are allowed due to substitution

backticks

Examples of incorrect code for this rule with the "backtick" option:

/*eslint quotes: ["error", "backtick"]*/

var single = 'single';
var double = "double";
var unescaped = 'a string containing `backticks`';

Examples of correct code for this rule with the "backtick" option:

/*eslint quotes: ["error", "backtick"]*/
/*eslint-env es6*/

var backtick = `backtick`;

avoidEscape

Examples of additional correct code for this rule with the "double", { "avoidEscape": true } options:

/*eslint quotes: ["error", "double", { "avoidEscape": true }]*/

var single = 'a string containing "double" quotes';

Examples of additional correct code for this rule with the "single", { "avoidEscape": true } options:

/*eslint quotes: ["error", "single", { "avoidEscape": true }]*/

var double = "a string containing 'single' quotes";

Examples of additional correct code for this rule with the "backtick", { "avoidEscape": true } options:

/*eslint quotes: ["error", "backtick", { "avoidEscape": true }]*/

var double = "a string containing `backtick` quotes"

allowTemplateLiterals

Examples of additional correct code for this rule with the "double", { "allowTemplateLiterals": true } options:

/*eslint quotes: ["error", "double", { "allowTemplateLiterals": true }]*/

var double = "double";
var double = `double`;

Examples of additional correct code for this rule with the "single", { "allowTemplateLiterals": true } options:

/*eslint quotes: ["error", "single", { "allowTemplateLiterals": true }]*/

var single = 'single';
var single = `single`;

{ "allowTemplateLiterals": false } will not disallow the usage of all template literals. If you want to forbid any instance of template literals, use no-restricted-syntax and target the TemplateLiteral selector.

When Not To Use It

If you do not need consistency in your string styles, you can safely disable this rule. Source: http://eslint.org/docs/rules/

Single Line Per Selector

Rule single-line-per-selector will enforce whether selectors should be placed on a new line.

Examples

When enabled, the following are allowed:

.foo,
.bar {
  content: 'baz';
}

When enabled, the following are disallowed:

.foo, .bar {
  content: 'baz';
}

Empty Line Between Blocks

Rule empty-line-between-blocks will enforce whether or not nested blocks should include a space between the last non-comment declaration or not.

Options

• include: true/false (defaults to true)
• allow-single-line-rulesets: true/false (defaults to true)

Examples

include

When include: true, the following are allowed. When include: false, the following are disallowed:

.foo {
  content: 'foo';

  .bar {
    content: 'bar';

    // Waldo
    &--baz {
      content: 'baz';
    }
  }
}

When include: false, the following are allowed. When include: true, the following are disallowed:

.foo {
  content: 'foo';
  .bar {
    content: 'bar';
    // Waldo
    &--baz {
      content: 'baz';
    }
  }
}

allow-single-line-rulesets

When allow-single-line-rulesets: true, the following are allowed. When allow-single-line-rulesets: false, the following are disallowed:

.foo { content: 'foo'; }
.bar { content: 'bar'; }
.baz { content: 'baz'; }

Single Line Per Selector

Rule single-line-per-selector will enforce whether selectors should be placed on a new line.

Examples

When enabled, the following are allowed:

.foo,
.bar {
  content: 'baz';
}

When enabled, the following are disallowed:

.foo, .bar {
  content: 'baz';
}

Empty Line Between Blocks

Rule empty-line-between-blocks will enforce whether or not nested blocks should include a space between the last non-comment declaration or not.

Options

• include: true/false (defaults to true)
• allow-single-line-rulesets: true/false (defaults to true)

Examples

include

When include: true, the following are allowed. When include: false, the following are disallowed:

.foo {
  content: 'foo';

  .bar {
    content: 'bar';

    // Waldo
    &--baz {
      content: 'baz';
    }
  }
}

When include: false, the following are allowed. When include: true, the following are disallowed:

.foo {
  content: 'foo';
  .bar {
    content: 'bar';
    // Waldo
    &--baz {
      content: 'baz';
    }
  }
}

allow-single-line-rulesets

When allow-single-line-rulesets: true, the following are allowed. When allow-single-line-rulesets: false, the following are disallowed:

.foo { content: 'foo'; }
.bar { content: 'bar'; }
.baz { content: 'baz'; }

Leading Zero

Rule leading-zero will enforce whether or not decimal numbers should include a leading zero.

Options

• include: true/false (defaults to false)

Examples

When include: false, the following are allowed. When include: true, the following are disallowed:

.foo {
  font-size: .5em;
}

When include: true, the following are allowed. When include: false, the following are disallowed:

.foo {
  font-size: 0.5em;
}

Single Line Per Selector

Rule single-line-per-selector will enforce whether selectors should be placed on a new line.

Examples

When enabled, the following are allowed:

.foo,
.bar {
  content: 'baz';
}

When enabled, the following are disallowed:

.foo, .bar {
  content: 'baz';
}

For more information visit Source: http://eslint.org/docs/rules/

For more information visit Source: http://eslint.org/docs/rules/

MD022 - Headers should be surrounded by blank lines

Tags: headers, blank_lines

Aliases: blanks-around-headers

This rule is triggered when headers (any style) are either not preceded or not followed by a blank line:

# Header 1
Some text

Some more text
## Header 2

To fix this, ensure that all headers have a blank line both before and after (except where the header is at the beginning or end of the document):

# Header 1

Some text

Some more text

## Header 2

Rationale: Aside from aesthetic reasons, some parsers, including kramdown, will not parse headers that don't have a blank line before, and will parse them as regular text.

MD026 - Trailing punctuation in header

Tags: headers

Aliases: no-trailing-punctuation

Parameters: punctuation (string; default ".,;:!?")

This rule is triggered on any header that has a punctuation character as the last character in the line:

# This is a header.

To fix this, remove any trailing punctuation:

# This is a header

Note: The punctuation parameter can be used to specify what characters class as punctuation at the end of the header. For example, you can set it to '.,;:!' to allow headers with question marks in them, such as might be used in an FAQ.

Property Sort Order

Rule property-sort-order will enforce the order in which declarations are written.

Options

• order: 'alphabetical', 'concentric', 'recess', 'smacss', or [array of properties] (defaults to alphabetical. Unknown properties are sorted alphabetically)
• ignore-custom-properties: true/false (defaults to false)

Property orders: https://github.com/sasstools/sass-lint/tree/develop/lib/config/property-sort-orders

Examples

When enabled (assuming order: alphabetical), the following are allowed:

.foo {
  content: 'baz';
  height: 100vh;
  width: 100vw;
}

When enabled (assuming order: alphabetical), the following are disallowed:

.foo {
  width: 100vw;
  height: 100vh;
  content: 'baz';
}

Custom Sort Orders

You have the option to create your own custom property sort orders. These are specified in your .sass-lint.yml file as below:

property-sort-order:
  - 1
  -
    order:
      - border
      - display
      - color

When the custom order is specified as above, the following are allowed:

.foo {
  border: 1px solid blue;
  display: block;
  color: red;
}

When the custom order is specified as above, the following are disallowed:

.foo {
  display: block;
  color: red;
  border: 1px solid blue;
}

Ignore Custom Properties

When ignore-custom-properties: false (assume order: 'alphabetical') the following would be allowed

.foo {
  border: 1px solid blue;
  color: red;
  composes: heading;
  display: block;
}

When ignore-custom-properties: false (assume order: 'alphabetical') the following would be disallowed

.foo {
  composes: heading; // not in alphabetical order
  border: 1px solid blue;
  color: red;
  display: block;
}

When ignore-custom-properties: true (assume order: 'alphabetical') the following would be allowed

.foo {
  composes: heading; // custom properties ignored
  border: 1px solid blue;
  color: red;
  display: block;
}

Single Line Per Selector

Rule single-line-per-selector will enforce whether selectors should be placed on a new line.

Examples

When enabled, the following are allowed:

.foo,
.bar {
  content: 'baz';
}

When enabled, the following are disallowed:

.foo, .bar {
  content: 'baz';
}

For more information visit Source: http://eslint.org/docs/rules/

For more information visit Source: http://eslint.org/docs/rules/

MD022 - Headers should be surrounded by blank lines

Tags: headers, blank_lines

Aliases: blanks-around-headers

This rule is triggered when headers (any style) are either not preceded or not followed by a blank line:

# Header 1
Some text

Some more text
## Header 2

To fix this, ensure that all headers have a blank line both before and after (except where the header is at the beginning or end of the document):

# Header 1

Some text

Some more text

## Header 2

Rationale: Aside from aesthetic reasons, some parsers, including kramdown, will not parse headers that don't have a blank line before, and will parse them as regular text.

MD022 - Headers should be surrounded by blank lines

Tags: headers, blank_lines

Aliases: blanks-around-headers

This rule is triggered when headers (any style) are either not preceded or not followed by a blank line:

# Header 1
Some text

Some more text
## Header 2

To fix this, ensure that all headers have a blank line both before and after (except where the header is at the beginning or end of the document):

# Header 1

Some text

Some more text

## Header 2

Rationale: Aside from aesthetic reasons, some parsers, including kramdown, will not parse headers that don't have a blank line before, and will parse them as regular text.

Empty Line Between Blocks

Rule empty-line-between-blocks will enforce whether or not nested blocks should include a space between the last non-comment declaration or not.

Options

• include: true/false (defaults to true)
• allow-single-line-rulesets: true/false (defaults to true)

Examples

include

When include: true, the following are allowed. When include: false, the following are disallowed:

.foo {
  content: 'foo';

  .bar {
    content: 'bar';

    // Waldo
    &--baz {
      content: 'baz';
    }
  }
}

When include: false, the following are allowed. When include: true, the following are disallowed:

.foo {
  content: 'foo';
  .bar {
    content: 'bar';
    // Waldo
    &--baz {
      content: 'baz';
    }
  }
}

allow-single-line-rulesets

When allow-single-line-rulesets: true, the following are allowed. When allow-single-line-rulesets: false, the following are disallowed:

.foo { content: 'foo'; }
.bar { content: 'bar'; }
.baz { content: 'baz'; }

Property Sort Order

Rule property-sort-order will enforce the order in which declarations are written.

Options

• order: 'alphabetical', 'concentric', 'recess', 'smacss', or [array of properties] (defaults to alphabetical. Unknown properties are sorted alphabetically)
• ignore-custom-properties: true/false (defaults to false)

Property orders: https://github.com/sasstools/sass-lint/tree/develop/lib/config/property-sort-orders

Examples

When enabled (assuming order: alphabetical), the following are allowed:

.foo {
  content: 'baz';
  height: 100vh;
  width: 100vw;
}

When enabled (assuming order: alphabetical), the following are disallowed:

.foo {
  width: 100vw;
  height: 100vh;
  content: 'baz';
}

Custom Sort Orders

You have the option to create your own custom property sort orders. These are specified in your .sass-lint.yml file as below:

property-sort-order:
  - 1
  -
    order:
      - border
      - display
      - color

When the custom order is specified as above, the following are allowed:

.foo {
  border: 1px solid blue;
  display: block;
  color: red;
}

When the custom order is specified as above, the following are disallowed:

.foo {
  display: block;
  color: red;
  border: 1px solid blue;
}

Ignore Custom Properties

When ignore-custom-properties: false (assume order: 'alphabetical') the following would be allowed

.foo {
  border: 1px solid blue;
  color: red;
  composes: heading;
  display: block;
}

When ignore-custom-properties: false (assume order: 'alphabetical') the following would be disallowed

.foo {
  composes: heading; // not in alphabetical order
  border: 1px solid blue;
  color: red;
  display: block;
}

When ignore-custom-properties: true (assume order: 'alphabetical') the following would be allowed

.foo {
  composes: heading; // custom properties ignored
  border: 1px solid blue;
  color: red;
  display: block;
}