eslint/docs/rules/no-extra-label.md

   1 # Disallow Unnecessary Labels (no-extra-label)
   2
   3 If a loop contains no nested loops or switches, labeling the loop is unnecessary.
   4
   5 ```js
   6 A: while (a) {
   7     break A;
   8 }
   9 ```
  10
  11 You can achieve the same result by removing the label and using `break` or `continue` without a label.
  12 Probably those labels would confuse developers because they expect labels to jump to further.
  13
  14 ## Rule Details
  15
  16 This rule is aimed at eliminating unnecessary labels.
  17
  18 Examples of **incorrect** code for this rule:
  19
  20 ```js
  21 /*eslint no-extra-label: "error"*/
  22
  23 A: while (a) {
  24     break A;
  25 }
  26
  27 B: for (let i = 0; i < 10; ++i) {
  28     break B;
  29 }
  30
  31 C: switch (a) {
  32     case 0:
  33         break C;
  34 }
  35 ```
  36
  37 Examples of **correct** code for this rule:
  38
  39 ```js
  40 /*eslint no-extra-label: "error"*/
  41
  42 while (a) {
  43     break;
  44 }
  45
  46 for (let i = 0; i < 10; ++i) {
  47     break;
  48 }
  49
  50 switch (a) {
  51     case 0:
  52         break;
  53 }
  54
  55 A: {
  56     break A;
  57 }
  58
  59 B: while (a) {
  60     while (b) {
  61         break B;
  62     }
  63 }
  64
  65 C: switch (a) {
  66     case 0:
  67         while (b) {
  68             break C;
  69         }
  70         break;
  71 }
  72 ```
  73
  74 ## When Not To Use It
  75
  76 If you don't want to be notified about usage of labels, then it's safe to disable this rule.
  77
  78 ## Related Rules
  79
  80 * [no-labels](./no-labels.md)
  81 * [no-label-var](./no-label-var.md)
  82 * [no-unused-labels](./no-unused-labels.md)