eslint/docs/src/rules/yield-star-spacing.md

   1 ---
   2 title: yield-star-spacing
   3 rule_type: layout
   4 further_reading:
   5 - https://leanpub.com/understandinges6/read/#leanpub-auto-generators
   6 ---
   7
   8
   9
  10 ## Rule Details
  11
  12 This rule enforces spacing around the `*` in `yield*` expressions.
  13
  14 ## Options
  15
  16 The rule takes one option, an object, which has two keys `before` and `after` having boolean values `true` or `false`.
  17
  18 * `before` enforces spacing between the `yield` and the `*`.
  19   If `true`, a space is required, otherwise spaces are disallowed.
  20
  21 * `after` enforces spacing between the `*` and the argument.
  22   If it is `true`, a space is required, otherwise spaces are disallowed.
  23
  24 The default is `{"before": false, "after": true}`.
  25
  26 ```json
  27 "yield-star-spacing": ["error", {"before": true, "after": false}]
  28 ```
  29
  30 The option also has a string shorthand:
  31
  32 * `{"before": false, "after": true}` → `"after"`
  33 * `{"before": true, "after": false}` → `"before"`
  34 * `{"before": true, "after": true}` → `"both"`
  35 * `{"before": false, "after": false}` → `"neither"`
  36
  37 ```json
  38 "yield-star-spacing": ["error", "after"]
  39 ```
  40
  41 ## Examples
  42
  43 ### after
  44
  45 Examples of **correct** code for this rule with the default `"after"` option:
  46
  47 ::: correct
  48
  49 ```js
  50 /*eslint yield-star-spacing: ["error", "after"]*/
  51 /*eslint-env es6*/
  52
  53 function* generator() {
  54   yield* other();
  55 }
  56 ```
  57
  58 :::
  59
  60 ### before
  61
  62 Examples of **correct** code for this rule with the `"before"` option:
  63
  64 ::: correct
  65
  66 ```js
  67 /*eslint yield-star-spacing: ["error", "before"]*/
  68 /*eslint-env es6*/
  69
  70 function *generator() {
  71   yield *other();
  72 }
  73 ```
  74
  75 :::
  76
  77 ### both
  78
  79 Examples of **correct** code for this rule with the `"both"` option:
  80
  81 ::: correct
  82
  83 ```js
  84 /*eslint yield-star-spacing: ["error", "both"]*/
  85 /*eslint-env es6*/
  86
  87 function * generator() {
  88   yield * other();
  89 }
  90 ```
  91
  92 :::
  93
  94 ### neither
  95
  96 Examples of **correct** code for this rule with the `"neither"` option:
  97
  98 ::: correct
  99
 100 ```js
 101 /*eslint yield-star-spacing: ["error", "neither"]*/
 102 /*eslint-env es6*/
 103
 104 function*generator() {
 105   yield*other();
 106 }
 107 ```
 108
 109 :::
 110
 111 ## When Not To Use It
 112
 113 If your project will not be using generators or you are not concerned with spacing consistency, you do not need this rule.