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JavaScript BigInt

JavaScript BigInt variables are used to store big integer values that are too big to be represented by a normal JavaScript Number.

JavaScript Integer Accuracy

JavaScript integers are only accurate up to 15 digits:

Integer Precision

let x = 999999999999999;
let y = 9999999999999999;
Try it Yourself »

In JavaScript, all numbers are stored in a 64-bit floating-point format (IEEE 754 standard).

With this standard, large integer cannot be exactly represented and will be rounded.

Because of this, JavaScript can only safely represent integers:

Up to 9007199254740991 +(253-1)

and

Down to -9007199254740991 -(253-1).

Integer values outside this range lose precision.


How to Create a BigInt

To create a BigInt, append n to the end of an integer or call BigInt():

Examples

let x = 9999999999999999;
let y = 9999999999999999n;
Try it Yourself »
let x = 1234567890123456789012345n;
let y = BigInt(1234567890123456789012345)
Try it Yourself »

BigInt: A new JavaScript Datatype

The JavaScript typeof a BigInt is "bigint":

Example

let x = BigInt(999999999999999);
let type = typeof x;
Try it Yourself »

BigInt is the second numeric data type in JavaScript (after Number).

With BigInt the total number of supported data types in JavaScript is 8:

  • BigInt
  • Boolean
  • Null
  • Number
  • Object
  • String
  • Symbol
  • Undefined

BigInt Operators

Operators that can be used on a JavaScript Number can also be used on a BigInt.

BigInt Multiplication Example

let x = 9007199254740995n;
let y = 9007199254740995n;
let z = x * y;
Try it Yourself »

Notes

Arithmetic between a BigInt and a Number is not allowed (type conversion lose information).

Unsigned right shift (>>>) can not be done on a BigInt (it does not have a fixed width).


BigInt Decimals

A BigInt can not have decimals.

BigInt Division Example

let x = 5n;
let y = x / 2;
// Error: Cannot mix BigInt and other types, use explicit conversion.
let x = 5n;
let y = Number(x) / 2;
Try it Yourself »

BigInt Hex, Octal and Binary

BigInt can also be written in hexadecimal, octal, or binary notation:

BigInt Hex Example

let hex = 0x20000000000003n;
let oct = 0o400000000000000003n
let bin = 0b100000000000000000000000000000000000000000000000000011n;
Try it Yourself »

Precision Curiosity

Rounding can compromise program security:

MAX_SAFE_INTEGER Example

9007199254740992 === 9007199254740993; // is true !!!
Try it Yourself »

Browser Support

BigInt is supported in all browsers since September 2020:

Chrome 67 Edge 79 Firefox 68 Safari 14 Opera 54
May 2018 Jan 2020 Jul 2019 Sep 2020 Jun 2018


Minimum and Maximum Safe Integers

ES6 added max and min properties to the Number object:

  • MAX_SAFE_INTEGER
  • MIN_SAFE_INTEGER

MAX_SAFE_INTEGER Example

let x = Number.MAX_SAFE_INTEGER;
Try it Yourself »

MIN_SAFE_INTEGER Example

let x = Number.MIN_SAFE_INTEGER;
Try it Yourself »

New Number Methods

ES6 also added 2 new methods to the Number object:

  • Number.isInteger()
  • Number.isSafeInteger()

The Number.isInteger() Method

The Number.isInteger() method returns true if the argument is an integer.

Example: isInteger()

Number.isInteger(10);
Number.isInteger(10.5);
Try it Yourself »

The Number.isSafeInteger() Method

A safe integer is an integer that can be exactly represented as a double precision number.

The Number.isSafeInteger() method returns true if the argument is a safe integer.

Example isSafeInteger()

Number.isSafeInteger(10);
Number.isSafeInteger(12345678901234567890);
Try it Yourself »

Safe integers are all integers from -(253 - 1) to +(253 - 1).
This is safe: 9007199254740991. This is not safe: 9007199254740992.