JS: Number (class)

What is the Keyword “Number”

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

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

Type

Type of Number is a function.

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

Parent

Parent of Number is Function.prototype.

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

Purpose

Purpose of Number is:

• Implicitly called by JavaScript to convert a number Primitive Value to object type, so that you can call methods on numbers. e.g. toString.
• Used as a namespace to hold static methods.
• Holds the property key "prototype". Its value is the parent of all instance of number.

Number Constructor

• JS: Number Constructor

Properties

• JS: Number.prototype

• JS: Number.parseInt (String to Number)
• JS: Number.parseFloat (String to Number)
• JS: Number.isFinite
• JS: Number.isInteger
• JS: Number.isNaN
• JS: Number.isSafeInteger

Number.NaN

Value is NaN.

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

Number.NEGATIVE_INFINITY

Value is -Infinity.

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

• JS: Infinity

Number.POSITIVE_INFINITY

Value is +Infinity.

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

Number.MIN_SAFE_INTEGER

Value is -9007199254740991 (same as -(2^53-1)).

It's the smallest integer n such that n and n - 1 are both exactly representable as a Number value.

console.assert(Number.MIN_SAFE_INTEGER === -9007199254740991);
console.assert(-9007199254740991 === -(2 ** 53 - 1));

Number.MAX_SAFE_INTEGER

Value is 9007199254740991. Same as (2^53 - 1).

It's the largest integer n such that n and n + 1 are both exactly representable as a Number value.

console.assert(Number.MAX_SAFE_INTEGER === 9007199254740991);

Number.EPSILON

Value is the difference between 1 and the smallest value greater than 1 that is representable as a Number value, which is approximately 2.2204460492503130808472633361816 x 10^(-16).

console.assert(Number.EPSILON === 2.220446049250313e-16);

Number.MIN_VALUE

The value is the smallest positive value of the Number type, which is approximately 5 × 10^(-324).

In the IEEE 754-2008 double precision binary representation, the smallest possible value is a denormalized number. If an implementation does not support denormalized values, the value of Number.MIN_VALUE must be the smallest non-zero positive value that can actually be represented by the implementation.

console.assert(Number.MIN_VALUE === 5e-324);

Number.MAX_VALUE

The value is the largest positive finite value of the Number type, which is approximately 1.7976931348623157 × 10^308.

console.assert(Number.MAX_VALUE === 1.7976931348623157e+308);