noConfusingLabels

Diagnostic Category: lint/suspicious/noConfusingLabels

JavaScript (and super languages)

Since: v1.0.0

Sources:

Inspired from: no-labels

Description

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

Invalid

label: f();

code-block.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;
}

code-block.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;
}

code-block.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;
}

code-block.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

outer: while (a) {
    while(b) {
        break outer;
    }
}

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

How to configure

{
  "linter": {
    "rules": {
      "suspicious": {
        "noConfusingLabels": "error"
      }
    }
  }
}