void
Evaluates an expression and returns undefined.
Syntax
void expression
Returns
undefined — Always `undefined`, regardless of the operand.
Examples
console.log(void 0);
console.log(void "anything");
Output
undefined
undefined
// Force an IIFE to be parsed as an expression
void function () {
console.log("ran");
}();
Output
ran
const result = void (1 + 2);
console.log(result);
Output
undefined
Notes
- `void 0` is a reliable way to produce `undefined`.
- Historically used in `javascript:void(0)` links to prevent navigation.
- Can be used to discard the result of an async call lint-cleanly.
Browser & runtime support
| Environment | Since version |
|---|---|
| chrome | 1.0 |
| firefox | 1.0 |
| safari | 1.0 |
| edge | 12 |
| node | 0.10 |