Number.prototype.valueOf() - JavaScript 编辑

The valueOf() method returns the wrapped primitive value of a Number object.

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The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

Syntax

numObj.valueOf()

Return value

A number representing the primitive value of the specified Number object.

Description

This method is usually called internally by JavaScript and not explicitly in web code.

Examples

Using valueOf

let numObj = new Number(10)
console.log(typeof numObj)  // object

let num = numObj.valueOf()
console.log(num)            // 10
console.log(typeof num)     // number

Specifications

Specification
ECMAScript (ECMA-262) The definition of 'Number.prototype.valueOf' in that specification.

Browser compatibility

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See also

• Number.prototype.toSource()