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

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