JavaScript Number prototype

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Example

Create a new number method that returns a number's half value:

Number.prototype.myMethod = function() {
return this.valueOf() / 2;
};

Use the new method on a number:

let n = 55;
let x = n.myMethod();

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Description

prototype allows you to add new properties and methods to numbers.

prototype is a property available with all JavaScript objects.

Syntax

Number.prototype.name = value

Warning

You are not advised to change the prototype of an object that you do not control.

You should not change the prototype of built in JavaScript datatypes like:

Numbers
Strings
Arrays
Dates
Booleans
Function
Objects

Only change the prototype of your own objects.

The prototype Property

The JavaScript prototype property allows you to add new properties to objects:

Example

function Person(first, last, age, eyecolor) {
this.firstName = first;
this.lastName = last;
this.eyeColor = eyecolor;
}

Person.prototype.nationality = "English";

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Browser Support

Number.prototype is an ECMAScript1 (ES1) feature.

ES1 (JavaScript 1997) is fully supported in all browsers:


Chrome	Edge	Firefox	Safari	Opera	IE
Yes	Yes	Yes	Yes	Yes	Yes

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