Logical OR (||)
Returns the first truthy operand, or the last operand if all are falsy.
Syntax
left || right
Returns
any — `left` if it is truthy, otherwise `right`.
Examples
console.log(false || "fallback");
console.log("first" || "second");
Output
fallback
first
const name = "" || "anonymous";
console.log(name);
Output
anonymous
const count = 0 || 10;
console.log(count);
Output
10
Notes
- Short-circuits: `right` is only evaluated if `left` is falsy.
- Treats any falsy value as "missing"; use `??` when only `null` and
`undefined` should fall back.
Browser & runtime support
| Environment | Since version |
|---|---|
| chrome | 1.0 |
| firefox | 1.0 |
| safari | 1.0 |
| edge | 12 |
| node | 0.10 |