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noConfusingLabels (since v1.0.0)

Diagnostic Category: lint/suspicious/noConfusingLabels

Sources:

Disallow labeled statements that are not loops.

Labeled statements in JavaScript are used in conjunction with break and continue to control flow around multiple loops. Their use for other statements is suspicious and unfamiliar.

The rule ignores reactive Svelte statements in Svelte components.

Examples

Section titled Examples

Invalid

Section titled Invalid
label: f();
suspicious/noConfusingLabels.js:1:1 lint/suspicious/noConfusingLabels ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Unexpected label.
  
  > 1 │ label: f();
      │ ^^^^^
    2 │ 
  
  ℹ Only loops should be labeled.
    The use of labels for other statements is suspicious and unfamiliar.
  

label: {
    f();
    break label;
}
suspicious/noConfusingLabels.js:1:1 lint/suspicious/noConfusingLabels ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Unexpected label.
  
  > 1 │ label: {
      │ ^^^^^
    2 │     f();
    3 │     break label;
  
  ℹ Only loops should be labeled.
    The use of labels for other statements is suspicious and unfamiliar.
  

label: if (a) {
    f()
    break label;
}
suspicious/noConfusingLabels.js:1:1 lint/suspicious/noConfusingLabels ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Unexpected label.
  
  > 1 │ label: if (a) {
      │ ^^^^^
    2 │     f()
    3 │     break label;
  
  ℹ Only loops should be labeled.
    The use of labels for other statements is suspicious and unfamiliar.
  

label: switch (a) {
    case 0:
        break label;
}
suspicious/noConfusingLabels.js:1:1 lint/suspicious/noConfusingLabels ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Unexpected label.
  
  > 1 │ label: switch (a) {
      │ ^^^^^
    2 │     case 0:
    3 │         break label;
  
  ℹ Only loops should be labeled.
    The use of labels for other statements is suspicious and unfamiliar.

Valid

Section titled Valid
outer: while (a) {
    while(b) {
        break outer;
    }
}
<script>
$: { /* reactive block */ }
</script>
Section titled Related links