This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The valueOf() method of Boolean values returns the primitive value of a Boolean object.
const x = new Boolean();
console.log(x.valueOf());
// Expected output: false
const y = new Boolean("Mozilla");
console.log(y.valueOf());
// Expected output: true
valueOf()
None.
The primitive value of the given Boolean object.
The valueOf() method of Boolean returns the primitive value of a Boolean object or literal Boolean as a Boolean data type.
This method is usually called internally by JavaScript and not explicitly in code.
valueOf()
const x = new Boolean(); const myVar = x.valueOf(); // assigns false to myVar
| Desktop | Mobile | Server | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Opera | Safari | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | WebView Android | WebView on iOS | Bun | Deno | Node.js | |
valueOf |
1 | 12 | 1 | 4 | 1 | 18 | 4 | 10.1 | 1 | 1.0 | 4.4 | 1 | 1.0.0 | 1.0 | 0.10.0 |
© 2005–2025 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean/valueOf