JS: Number (class)

By Xah Lee. Date: 2017-03-24. Last updated: 2026-07-23.

What is the Keyword “Number”

Number is the value of the property key "Number" of the Global Object .

console.assert(globalThis["Number"] === Number);

Type of Number is a function.

console.assert(typeof Number === "function");

console.assert(Reflect.getPrototypeOf(Number) === Function.prototype);

Purpose of Number is:

A Primitive Value object wrapper.
Used as a namespace to hold static methods.
Holds the property key "prototype". Its value is the parent of all number object.

Number.NaN

Value is NaN.

console.assert(Number.isNaN(Number.NaN));

Number.NEGATIVE_INFINITY

Value is -Infinity.

console.assert(Number.NEGATIVE_INFINITY === -Infinity);

Number.POSITIVE_INFINITY

Value is +Infinity.

console.assert(Number.POSITIVE_INFINITY === Infinity);