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noFallthroughSwitchClause (since v1.0.0)

Diagnostic Category: lint/suspicious/noFallthroughSwitchClause

Sources:

Disallow fallthrough of switch clauses.

Switch clauses in switch statements fall through by default. This can lead to unexpected behavior when forgotten.

The rule doesn’t take process.exit() in consideration.

Examples

Section titled Examples

Invalid

Section titled Invalid
switch (bar) {
  case 0:
    a();
  case 1:
    b();
}
suspicious/noFallthroughSwitchClause.js:2:2 lint/suspicious/noFallthroughSwitchClause ━━━━━━━━━━━━━━

  ✖ This case is falling through to the next case.
  
    1 │ switch (bar) {
  > 2 │ 	case 0:
      │ 	^^^^^^^
  > 3 │ 		a();
      │ 		^^^^
    4 │ 	case 1:
    5 │ 		b();
  
  ℹ Add a `break` or `return` statement to the end of this case to prevent fallthrough.

Valid

Section titled Valid
switch (foo) {
  case 1:
    case 2:
    doSomething();
    break;
    case 3: {
        if (cond) {
            break;
        } else {
            break;
        }
    }
  case 4:
    doSomething();
}
Section titled Related links