Xxhash Wasm Versions Save

A WebAssembly implementation of xxHash


7 months ago
  • Add support for Typescript's nodenext module resolution (#33)


1 year ago
  • Export data types separately + fixed bigint data type (#28)


1 year ago

This big release includes an up to a 3-4x performance improvement in most cases and a new streaming API similar to Node's built-in crypto API. To fully utilise the performance improvements, there are some breaking changes in the API and new engine requirements.

3-4x Performance improvements

To achieve these substantial performance improvements, a handful of new features have been used, which are fairly recent additions to the browsers, Node and the WebAssembly specification. These include the following:

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

Taking all of these requirements into account, v1.0.0 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.

Besides the features regarding memory optimisations for WebAssembly, the biggest addition is the use of BigInt, which avoids the whole workaround that was previously used in order to represent u64 integers in JavaScript. That makes everything a lot simpler and faster, but that also brings some breaking changes of the 64-bit API.

The TextEncoder.encodeInto allows encode the string as UTF-8 bytes directly into the WebAssembly memory, meaning that if you have the string and hash it directly, it will be faster than encoding it yourself and then using the Raw API. 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.

Streaming API

The streaming API allows to build up the input that is being hashed in an iterative manner, which is particularly helpful for larger inputs which are collected over time instead of having it all at once in memory. It is kept in line with Node's crypto.createHash, hence the streams are initialised with create32/create64 and then .update(string | Uint8Array) is used to add an input, which can either be a string or a Uint8Array, and finally .digest() needs to be called to finalise the hash.

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

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

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

Breaking Changes

64-bit seed as BigInt

64-bit hash APIs now use BigInt, where the seed is now a single BigInt instead of being split into the two halves seedHigh and seedLow. This makes it much simpler to use and avoids any workarounds for previous limitations.

0.4.2 1.0.0
h64(input: string, [seedHigh: u32, seedLow: u32]): string
h64Raw(input: Uint8Array, [seedHigh: u32, seedLow: u32]): Uint8Array
h64(input: string, [seed: BigInt]): BigInt
h64ToString(input: string, [seed: BigInt]): string
h64Raw(input: Uint8Array, [seed: BigInt]): BigInt

h32/h64 return numbers instead of strings

The hashes are numbers but were previously converted to a string of their a zero-padded hex string representations, mainly to keep the 32-bit in line with the 64-bit version, which could not be expressed by a single number without BigInt. This overhead is unnecessary for many applications and therefore the performance suffers. Now h32 returns a number and h64 a BigInt. For convenience, h32ToString and h64ToString have been added to get the hash as a string, which can also be achieved by converting them manually, e.g. hash64.toString(16).padStart(16, "0").

0.4.2 1.0.0
h32(input: string, [seed: u32]): string
h64(input: string, [seedHigh: u32, seedLow: u32]): string
h32(input: string, [seed: u32]): number
h64(input: string, [seed: BigInt]): BigInt

// New *ToString methods for convenience and to get old behaviour
h32ToString(input: string, [seed: u32]): string
h64ToString(input: string, [seed: BigInt]): string


1 year ago
  • Fix 64-bit hex representation when second part has leading zeros (#23)


3 years ago
  • TypeScript definitions
  • h32Raw and h64Raw APIs for use with Uint8Array