eslint/docs/src/rules/switch-colon-spacing.md

   1 ---
   2 title: switch-colon-spacing
   3 layout: doc
   4 rule_type: layout
   5 ---
   6
   7
   8
   9 Spacing around colons improves readability of `case`/`default` clauses.
  10
  11 ## Rule Details
  12
  13 This rule controls spacing around colons of `case` and `default` clauses in `switch` statements.
  14 This rule does the check only if the consecutive tokens exist on the same line.
  15
  16 This rule has 2 options that are boolean value.
  17
  18 ```json
  19 {
  20     "switch-colon-spacing": ["error", {"after": true, "before": false}]
  21 }
  22 ```
  23
  24 * `"after": true` (Default) requires one or more spaces after colons.
  25 * `"after": false` disallows spaces after colons.
  26 * `"before": true` requires one or more spaces before colons.
  27 * `"before": false` (Default) disallows before colons.
  28
  29 Examples of **incorrect** code for this rule:
  30
  31 ::: incorrect
  32
  33 ```js
  34 /*eslint switch-colon-spacing: "error"*/
  35
  36 switch (a) {
  37     case 0 :break;
  38     default :foo();
  39 }
  40 ```
  41
  42 :::
  43
  44 Examples of **correct** code for this rule:
  45
  46 ::: correct
  47
  48 ```js
  49 /*eslint switch-colon-spacing: "error"*/
  50
  51 switch (a) {
  52     case 0: foo(); break;
  53     case 1:
  54         bar();
  55         break;
  56     default:
  57         baz();
  58         break;
  59 }
  60 ```
  61
  62 :::
  63
  64 Examples of **incorrect** code for this rule with `{"after": false, "before": true}` option:
  65
  66 ::: incorrect
  67
  68 ```js
  69 /*eslint switch-colon-spacing: ["error", {"after": false, "before": true}]*/
  70
  71 switch (a) {
  72     case 0: break;
  73     default: foo();
  74 }
  75 ```
  76
  77 :::
  78
  79 Examples of **correct** code for this rule with `{"after": false, "before": true}` option:
  80
  81 ::: correct
  82
  83 ```js
  84 /*eslint switch-colon-spacing: ["error", {"after": false, "before": true}]*/
  85
  86 switch (a) {
  87     case 0 :foo(); break;
  88     case 1 :
  89         bar();
  90         break;
  91     default :
  92         baz();
  93         break;
  94 }
  95 ```
  96
  97 :::
  98
  99 ## When Not To Use It
 100
 101 If you don't want to notify spacing around colons of switch statements, then it's safe to disable this rule.