eslint/docs/rules/lines-between-class-members.md

   1 # require or disallow an empty line between class members (lines-between-class-members)
   2
   3 This rule improves readability by enforcing lines between class members. It will not check empty lines before the first member and after the last member, since that is already taken care of by padded-blocks.
   4
   5 ## Rule Details
   6
   7 Examples of **incorrect** code for this rule:
   8
   9 ```js
  10 /* eslint lines-between-class-members: ["error", "always"]*/
  11 class MyClass {
  12   x;
  13   foo() {
  14     //...
  15   }
  16   bar() {
  17     //...
  18   }
  19 }
  20 ```
  21
  22 Examples of **correct** code for this rule:
  23
  24 ```js
  25 /* eslint lines-between-class-members: ["error", "always"]*/
  26 class MyClass {
  27   x;
  28
  29   foo() {
  30     //...
  31   }
  32
  33   bar() {
  34     //...
  35   }
  36 }
  37 ```
  38
  39 Examples of additional **correct** code for this rule:
  40
  41 ```js
  42 /* eslint lines-between-class-members: ["error", "always"]*/
  43 class MyClass {
  44   x = 1
  45
  46   ;in = 2
  47 }
  48 ```
  49
  50 ### Options
  51
  52 This rule has a string option and an object option.
  53
  54 String option:
  55
  56 * `"always"`(default) require an empty line after class members
  57 * `"never"` disallows an empty line after class members
  58
  59 Object option:
  60
  61 * `"exceptAfterSingleLine": false`(default) **do not** skip checking empty lines after single-line class members
  62 * `"exceptAfterSingleLine": true` skip checking empty lines after single-line class members
  63
  64 Examples of **incorrect** code for this rule with the string option:
  65
  66 ```js
  67 /* eslint lines-between-class-members: ["error", "always"]*/
  68 class Foo{
  69   x;
  70   bar(){}
  71   baz(){}
  72 }
  73
  74 /* eslint lines-between-class-members: ["error", "never"]*/
  75 class Foo{
  76   x;
  77
  78   bar(){}
  79
  80   baz(){}
  81 }
  82 ```
  83
  84 Examples of **correct** code for this rule with the string option:
  85
  86 ```js
  87 /* eslint lines-between-class-members: ["error", "always"]*/
  88 class Foo{
  89   x;
  90
  91   bar(){}
  92
  93   baz(){}
  94 }
  95
  96 /* eslint lines-between-class-members: ["error", "never"]*/
  97 class Foo{
  98   x;
  99   bar(){}
 100   baz(){}
 101 }
 102 ```
 103
 104 Examples of **correct** code for this rule with the object option:
 105
 106 ```js
 107 /* eslint lines-between-class-members: ["error", "always", { "exceptAfterSingleLine": true }]*/
 108 class Foo{
 109   x; // single line class member
 110   bar(){} // single line class member
 111   baz(){
 112     // multi line class member
 113   }
 114
 115   qux(){}
 116 }
 117 ```
 118
 119 ## When Not To Use It
 120
 121 If you don't want to enforce empty lines between class members, you can disable this rule.
 122
 123 ## Related Rules
 124
 125 * [padded-blocks](padded-blocks.md)
 126 * [padding-line-between-statements](padding-line-between-statements.md)
 127
 128 ## Compatibility
 129
 130 * [requirePaddingNewLinesAfterBlocks](https://jscs-dev.github.io/rule/requirePaddingNewLinesAfterBlocks)
 131 * [disallowPaddingNewLinesAfterBlocks](https://jscs-dev.github.io/rule/disallowPaddingNewLinesAfterBlocks)