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xxhash-wasm (with workerd support)

Deprecated

The changes in this repo have now been upstreamed.

This is a fork of jungomi/xxhash-wasm with added support for Cloudflare Workers. This is done by introducing a conditional export.

Node.js npm

🚨 *** The v1.0.0 release brought an up to 3-4x performance improvement and a streaming API. There were some breaking changes and new engine requirements. For details see the v1.0.0 release notes, which can also be found in the CHANGELOG.md.***

A WebAssembly implementation of xxHash, a fast non-cryptographic hash algorithm. It can be called seamlessly from JavaScript. You can use it like any other JavaScript library but still get the benefits of WebAssembly, no special setup needed.

Table of Contents

Installation

From npm

npm install --save xxhash-wasm

Or with Yarn:

yarn add xxhash-wasm

From Unpkg

ES Modules

<script type="module">
  import xxhash from "https://unpkg.com/xxhash-wasm/esm/xxhash-wasm.js";
</script>

UMD build

<script src="https://unpkg.com/xxhash-wasm/umd/xxhash-wasm.js"></script>

The global xxhash will be available.

Usage

The WebAssembly is contained in the JavaScript bundle, so you don't need to manually fetch it and create a new WebAssembly instance.

import xxhash from "xxhash-wasm";

// Creates the WebAssembly instance.
xxhash().then(hasher => {
  const input = "The string that is being hashed";

  // 32-bit version
  hasher.h32(input); // 3998627172 (decimal representation)
  // For convenience, get hash as string of its zero-padded hex representation
  hasher.h32ToString(input); // "ee563564"

  // 64-bit version
  hasher.h64(input); // 5776724552493396044n (BigInt)
  // For convenience, get hash as string of its zero-padded hex representation
  hasher.h64ToString(input); // "502b0c5fc4a5704c"
});

Or with async/await and destructuring:

// Creates the WebAssembly instance.
const { h32, h64 } = await xxhash();

const input = "The string that is being hashed";
// 32-bit version
h32(input); // 3998627172 (decimal representation)
// 64-bit version
h64(input); // 5776724552493396044n (BigInt)

Streaming Example

xxhash-wasm supports a crypto-like streaming api, useful for avoiding memory consumption when hashing large amounts of data:

const { create32, create64 } = await xxhash();

// 32-bit version
create32()
  .update("some data")
  // update accepts either a string or Uint8Array
  .update(Uint8Array.from([1, 2, 3]))
  .digest(); // 955607085

// 64-bit version
create64()
  .update("some data")
  // update accepts either a string or Uint8Array
  .update(Uint8Array.from([1, 2, 3]))
  .digest(); // 883044157688673477n

Node

It doesn't matter whether you are using CommonJS or ES Modules in Node (e.g. with "type": "module" in package.json or using the explicit file extensions .cjs or .mjs respectively), importing xxhash-wasm will always load the corresponding module, as both bundles are provided and specified in the exports field of its package.json, therefore the appropriate one will automatically be selected.

Using ES Modules

import xxhash from "xxhash-wasm";

Using CommonJS

const xxhash = require("xxhash-wasm");

Performance

For performance sensitive applications, xxhash-wasm provides the h** and h**Raw APIs, which return raw numeric hash results rather than zero-padded hex strings. The overhead of the string conversion in the h**ToString APIs can be as much as 20% of overall runtime when hashing small byte-size inputs, and the string result is often inconsequential (for example when simply checking if the the resulting hashes are the same). When necessary, getting a zero-padded hex string from the provided number or BigInt results is easily achieved via result.toString(16).padStart(16, "0") and the h**ToString APIs are purely for convenience.

The h**, h**ToString, and streaming APIs make use of TextEncoder.encodeInto to directly encode strings as a stream of UTF-8 bytes into the WebAssembly memory buffer, meaning that for string-hashing purposes, these APIs will be significantly faster than converting the string to bytes externally and using the Raw API. That said, for large strings it may be beneficial to consider the streaming API or another approach to encoding, as encodeInto is forced to allocate 3-times the string length to account for the chance the input string contains high-byte-count code units.

If possible, defer the encoding of the string to the hashing, unless you need to use the encoded string (bytes) for other purposes as well, or you are creating the bytes differently (e.g. different encoding), in which case it's much more efficient to use the h**Raw APIs instead of having to unnecessarily convert them to a string first.

Engine Requirements

In an effort to make this library as performant as possible, it uses several recent additions to browsers, Node and the WebAssembly specification. Notably, these include:

  1. BigInt support in WebAssembly
  2. Bulk memory operations in WebAssembly
  3. TextEncoder.encodeInto

Taking all of these requirements into account, xxhash-wasm should be compatible with:

  • Chrome >= 85
  • Edge >= 79
  • Firefox >= 79
  • Safari >= 15.0
  • Node >= 15.0

If support for an older engine is required, [email protected] is available with much broader engine support, but 3-4x slower hashing performance.

API

const {
  h32,
  h32ToString,
  h32Raw,
  create32,
  h64,
  h64ToString,
  h64Raw,
  create64,
} = await xxhash();

Create a WebAssembly instance.

h32

h32(input: string, [seed: u32]): number

Generate a 32-bit hash of the UTF-8 encoded bytes of input. The optional seed is a u32 and any number greater than the maximum (0xffffffff) is wrapped, which means that 0xffffffff + 1 = 0.

Returns a u32 number containing the hash value.

h32ToString(input: string, [seed: u32]): string

Same as h32, but returning a zero-padded hex string.

h32Raw(input: Uint8Array, [seed: u32]): number

Same as h32 but with a Uint8Array as input instead of a string.

h64

h64(input: string, [seed: bigint]): bigint

Generate a 64-bit hash of the UTF-8 encoded bytes of input. The optional seed is a u64 provided as a BigInt.

Returns a u64 bigint containing the hash value.

h64ToString(input: string, [seed: bigint]): string

Same as h64, but returning a zero-padded hex string.

h64Raw(input: Uint8Array, [seed: bigint]): bigint

Same as h64 but with a Uint8Array as input instead of a string.

Streaming

type XXHash<T> {
  update(input: string | Uint8Array): XXHash<T>;
  digest(): T
}

The streaming API mirrors Node's built-in crypto.createHash, providing update and digest methods to add data to the hash and compute the final hash value, respectively.

create32([seed: number]): XXHash<number>

Create a 32-bit hash for streaming applications.

create64([seed: bigint]): XXHash<bigint>

Create a 64-bit hash for streaming applications.

Comparison to xxhashjs

xxhashjs is implemented in pure JavaScript and because JavaScript is lacking support for 64-bit integers, it uses a workaround with cuint. Not only is that a big performance hit, but it also increases the bundle size by quite a bit when it's used in the browser.

This library (xxhash-wasm) has the big advantage that WebAssembly supports u64 and also some instructions (e.g. rotl), which would otherwise have to be emulated. However, The downside is that you have to initialise a WebAssembly instance, which takes a little over 2ms in Node and about 1ms in the browser. But once the instance is created, it can be used without any further overhead. For the benchmarks below, the instantiation is done before the benchmark and therefore it's excluded from the results, since it wouldn't make sense to always create a new WebAssembly instance.

Benchmarks

Benchmarks are using Benchmark.js with random strings of different lengths. Higher is better

String length xxhashjs 32-bit xxhashjs 64-bit xxhash-wasm 32-bit xxhash-wasm 64-bit
1 byte 513,517 ops/sec 11,896 ops/sec 5,752,446 ops/sec 4,438,501 ops/sec
10 bytes 552,133 ops/sec 12,953 ops/sec 6,240,640 ops/sec 4,855,340 ops/sec
100 bytes 425,277 ops/sec 10,838 ops/sec 5,470,011 ops/sec 4,314,904 ops/sec
1,000 bytes 102,165 ops/sec 6,697 ops/sec 3,283,526 ops/sec 3,332,556 ops/sec
10,000 bytes 13,010 ops/sec 1,452 ops/sec 589,068 ops/sec 940,350 ops/sec
100,000 bytes 477 ops/sec 146 ops/sec 61,824 ops/sec 98,959 ops/sec
1,000,000 bytes 36.40 ops/sec 12.93 ops/sec 5,122 ops/sec 8,632 ops/sec
10,000,000 bytes 3.12 ops/sec 1.19 ops/sec 326 ops/sec 444 ops/sec
100,000,000 bytes 0.31 ops/sec 0.13 ops/sec 27.84 ops/sec 34.56 ops/sec

xxhash-wasm outperforms xxhashjs significantly, the 32-bit is up to 90 times faster (generally increases as the size of the input grows), and the 64-bit is up to 350 times faster (generally increases as the size of the input grows).

The 64-bit version is the faster algorithm but there is a small degree of overhead involved in using BigInts, and so it retains a performance advantage over all lengths over xxhashjs and the 32-bit algorithm above ~1000 bytes.

xxhash-wasm also significantly outperforms Node's built-in hash algorithms, making it suitable for use in a wide variety of situations, where non-cryptographic hashes are acceptable. Benchmarks from an x64 MacBook Pro running Node 17.3:

String length Node crypto md5 Node crypto sha1 xxhash-wasm 64-bit
1 byte 342,924 ops/sec 352,825 ops/sec 4,438,501 ops/sec
10 bytes 356,596 ops/sec 352,209 ops/sec 4,855,340 ops/sec
100 bytes 354,898 ops/sec 355,024 ops/sec 4,314,904 ops/sec
1,000 bytes 249,242 ops/sec 271,383 ops/sec 3,332,556 ops/sec
10,000 bytes 62,896 ops/sec 80,986 ops/sec 940,350 ops/sec
100,000 bytes 7,316 ops/sec 10,198 ops/sec 98,959 ops/sec
1,000,000 bytes 698 ops/sec 966 ops/sec 8,632 ops/sec
10,000,000 bytes 58.98 ops/sec 79.78 ops/sec 444 ops/sec
100,000,000 bytes 6.30 ops/sec 8.20 ops/sec 34.56 ops/sec

If suitable for your use case, the Raw API offers significant throughput improvements over the string-hashing API, particularly for smaller inputs, assuming that you have access to the Uint8Array already (see also the Performance section):

String length xxhash-wasm 64-bit Raw xxhash-wasm 64-bit
1 byte 9,342,811 ops/sec 4,438,501 ops/sec
10 bytes 9,668,989 ops/sec 4,855,340 ops/sec
100 bytes 8,775,845 ops/sec 4,314,904 ops/sec
1,000 bytes 5,541,403 ops/sec 3,332,556 ops/sec
10,000 bytes 1,079,866 ops/sec 940,350 ops/sec
100,000 bytes 113,350 ops/sec 98,959 ops/sec
1,000,000 bytes 9,779 ops/sec 8,632 ops/sec
10,000,000 bytes 563 ops/sec 444 ops/sec
100,000,000 bytes 43.77 ops/sec 34.56 ops/sec

Bundle size

Both libraries can be used in the browser and they provide a UMD bundle. The bundles are self-contained, that means they can be included and used without having to add any other dependencies. The table shows the bundle size of the minified versions. Lower is better.

xxhashjs xxhash-wasm
Bundle size 41.5kB 11.4kB
Gzipped Size 10.3kB 2.3kB