fnv1a

FNV-1a non-cryptographic hash function

FNV-1a has outstanding distribution and collisions are rare.

FNV hashes are designed to be fast while maintaining a low collision rate. The FNV speed allows one to quickly hash lots of data while maintaining a reasonable collision rate. The high dispersion of the FNV hashes makes them well suited for hashing nearly identical strings such as URLs, hostnames, filenames, text, IP addresses, etc.

Install

npm install @sindresorhus/fnv1a

Usage

import fnv1a from '@sindresorhus/fnv1a';

fnv1a('🦄🌈', {size: 32});
//=> 2868248295n

fnv1a('🦄🌈', {size: 128});
//=> 13487074350300261116944693128525960095n

Number(fnv1a('🦄🌈', {size: 32}));
//=> 2868248295

const bytes = new Uint8Array([240, 159, 166, 132, 240, 159, 140, 136]);
fnv1a(bytes, {size: 32});
//=> 2868248295n

API

fnv1a(value, options?)

Returns the hash as a positive BigInt.

If you need it as a number, use 32 as size and wrap the return value in Number(…).

value

Type: string | Uint8Array

A string or UTF-8 bytes.

options

Type: object

size

Type: number
Values: 32 | 64 | 128 | 256 | 512 | 1024
Default: 32

The bit size of the hash.

utf8Buffer

Type: Uint8Array

A Uint8Array used to encode the string into UTF-8 bytes.

This array can be reused across calls to fnv1a. Doing so will improve performance because it avoids allocating a new Uint8Array when encoding the string.

The size of the array does not have to be large enugh to hold the entire string, but performance will be improved if it is.

This option is only used when value is a string.

import fnv1a from '@sindresorhus/fnv1a';

const utf8Buffer = new Uint8Array(100);

fnv1a('🦄🌈', {size: 32, utf8Buffer});
//=> 2868248295n

Related

• djb2a - DJB2a non-cryptographic hash function
• sdbm - SDBM non-cryptographic hash function