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noUnusedLabels (since v1.0.0)

Diagnostic Category: lint/correctness/noUnusedLabels

Sources:

Disallow unused labels.

Labels that are declared and never used are most likely an error due to incomplete refactoring.

The rule ignores reactive Svelte statements in Svelte components.

Examples

Section titled Examples

Invalid

Section titled Invalid
LOOP: for (const x of xs) {
    if (x > 0) {
        break;
    }
    f(x);
}
correctness/noUnusedLabels.js:1:1 lint/correctness/noUnusedLabels  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Unused label.
  
  > 1 │ LOOP: for (const x of xs) {
      │ ^^^^
    2 │     if (x > 0) {
    3 │         break;
  
  ℹ The label is not used by any break statement and continue statement.
  
  ℹ Safe fix: Remove the unused label.
  
    1 │ LOOP:·for·(const·x·of·xs)·{
      │ ------

Valid

Section titled Valid
LOOP: for (const x of xs) {
    if (x > 0) {
        break LOOP;
    }
    f(x);
}
function nonNegative(n) {
    DEV: assert(n >= 0);
    return n;
}
<script>
$: { /* reactive block */ }
</script>
Section titled Related links