# Number

The `Number` JavaScript object is a wrapper object allowing you to work with numerical values. A `Number` object is created using the `Number()` constructor.

## Syntax

JavaScript
`new Number(value);`

### Parameters

`value`
The numeric value of the object being created.

## Description

The primary uses for the `Number` object are:

• If the argument cannot be converted into a number, it returns `NaN`.
• In a non-constructor context (i.e., without the `new` operator), `Number` can be used to perform a type conversion.

## Properties

`Number.EPSILON`
The smallest interval between two representable numbers.
`Number.MAX_SAFE_INTEGER`
The maximum safe integer in JavaScript (`253 - 1`).
`Number.MAX_VALUE`
The largest positive representable number.
`Number.MIN_SAFE_INTEGER`
The minimum safe integer in JavaScript (`-(253 - 1)`).
`Number.MIN_VALUE`
The smallest positive representable number - that is, the positive number closest to zero (without actually being zero).
`Number.NaN`
Special "not a number" value.
`Number.NEGATIVE_INFINITY`
Special value representing negative infinity; returned on overflow.
`Number.POSITIVE_INFINITY`
Special value representing infinity; returned on overflow.
`Number.prototype`
Allows the addition of properties to a `Number` object.

## Methods

`Number.isNaN()`
Determine whether the passed value is NaN.
`Number.isFinite()`
Determine whether the passed value is a finite number.
`Number.isInteger()`
Determine whether the passed value is an integer.
`Number.isSafeInteger()`
Determine whether the passed value is a safe integer (number between `-(253 - 1)` and `253 - 1`).
`Number.toInteger()`
Used to evaluate the passed value and convert it to an integer (or `Infinity`), but has been removed.
`Number.parseFloat()`
The value is the same as `parseFloat()` of the global object.
`Number.parseInt()`
The value is the same as `parseInt()` of the global object.

## `Number` instances

All `Number` instances inherit from `Number.prototype`. The prototype object of the `Number` constructor can be modified to affect all `Number` instances.

### Methods

`Number.prototype.toExponential()`
Returns a string representing the number in exponential notation.
`Number.prototype.toFixed()`
Returns a string representing the number in fixed-point notation.
`Number.prototype.toLocaleString()`
Returns a string with a language sensitive representation of this number. Overrides the `Object.prototype.toLocaleString()` method.
`Number.prototype.toPrecision()`
Returns a string representing the number to a specified precision in fixed-point or exponential notation.
`Number.prototype.toSource()`
Returns an object literal representing the specified `Number` object; you can use this value to create a new object. Overrides the `Object.prototype.toSource()` method.
`Number.prototype.toString()`
Returns a string representing the specified object in the specified radix (base). Overrides the `Object.prototype.toString()` method.
`Number.prototype.valueOf()`
Returns the primitive value of the specified object. Overrides the `Object.prototype.valueOf()` method.

## Examples

### Using the `Number` object to assign values to numeric variables

The following example uses the `Number` object's properties to assign values to several numeric variables:

JavaScript
```var biggestNum = Number.MAX_VALUE;
var smallestNum = Number.MIN_VALUE;
var infiniteNum = Number.POSITIVE_INFINITY;
var negInfiniteNum = Number.NEGATIVE_INFINITY;
var notANum = Number.NaN;```

### Integer range for `Number`

The following example shows minimum and maximum integer values that can be represented as `Number` object (for details, refer to ECMAScript standard, chapter 8.5 The Number Type):

JavaScript
```var biggestInt = 9007199254740992;
var smallestInt = -9007199254740992;```

When parsing data that has been serialized to JSON, integer values falling out of this range can be expected to become corrupted when JSON parser coerces them to `Number` type. Using `String` instead is a possible workaround.

### Using `Number` to convert a `Date` object

The following example converts the `Date` object to a numerical value using `Number` as a function:

JavaScript
```var d = new Date('December 17, 1995 03:24:00');
console.log(Number(d));```

This logs "819199440000".

### Convert numeric strings to numbers

JavaScript
```Number("123")     // 123
Number("12.3")    // 12.3
Number("")        // 0
Number("0x11")    // 17
Number("0b11")    // 3
Number("0o11")    // 9
Number("foo")     // NaN
Number("100a")    // NaN```

## Specifications

Specification Status Comment
ECMAScript 1st Edition (ECMA-262) Standard Initial definition. Implemented in JavaScript 1.1.
ECMAScript 5.1 (ECMA-262)
The definition of 'Number' in that specification.
Standard
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Number' in that specification.
Standard New methods and properties added: `EPSILON`, `isFinite`, `isInteger`, `isNaN`, `parseFloat`, `parseInt`
ECMAScript 2017 Draft (ECMA-262)
The definition of 'Number' in that specification.
Draft

## Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) (Yes) (Yes) (Yes) (Yes)
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)