noUnusedLabels

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JavaScript (and super languages)

Summary

Rule available since: v1.0.0
Diagnostic Category: lint/correctness/noUnusedLabels
This rule is recommended, which means is enabled by default.
This rule has a safe fix.
The default severity of this rule is warning.
Sources:
- Same as no-unused-labels

Description

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

Invalid

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LOOP: for (const x of xs) {
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    if (x > 0) {
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        break;
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    }
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    f(x);
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}

code-block.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

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LOOP: for (const x of xs) {
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    if (x > 0) {
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        break LOOP;
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    }
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    f(x);
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}

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function nonNegative(n) {
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    DEV: assert(n >= 0);
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    return n;
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}

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<script>
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$: { /* reactive block */ }
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</script>

How to configure

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{
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  "linter": {
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    "rules": {
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      "correctness": {
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        "noUnusedLabels": "error"
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      }
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    }
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  }
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}