MurmurHash3 32-bit

1.0.0 · active · verified Sun Apr 19

murmur-32 provides a JavaScript implementation of the MurmurHash3 algorithm for x86 32-bit systems. It's a non-cryptographic hash function known for its speed and good distribution properties, often used in hash tables, Bloom filters, and other data structures where collision resistance is less critical than performance. The current stable version is 1.0.0, released in July 2021. The package maintains a relatively slow release cadence, primarily focusing on stability and adherence to modern JavaScript standards. A key differentiator is its straightforward API for hashing both `ArrayBuffer` and string inputs, with strings being UTF-8 encoded by default since version 0.2.0, providing predictable cross-platform behavior.

Common errors

```
ReferenceError: require is not defined
```
cause Attempting to use `require()` to import `murmur-32` in a modern Node.js or browser ESM context after upgrading to version 1.0.0 or later.

fix Change your import statement to `import murmur32 from 'murmur-32';`.
```
Hash mismatch for string inputs after upgrade
```
cause Upgrading from `murmur-32` v0.1.0 to v0.2.0 or later, where the string encoding for hash inputs changed from UCS-2 to UTF-8, resulting in different hash values for the same string.

fix If you require the previous UCS-2 encoding behavior, pre-process your string inputs using `array-buffer-from-string`: `import arrayBufferFromString from 'array-buffer-from-string'; murmur32(arrayBufferFromString(yourString, 'ucs2'))`. Otherwise, update your application to expect UTF-8 encoded hash outputs.

Warnings

breaking Version 1.0.0 converted the package to an ECMAScript Module (ESM) and dropped CommonJS support. Direct `require()` statements will no longer work, and older Node.js versions are unsupported.
Fix: Update your import statements from `const murmur32 = require('murmur-32')` to `import murmur32 from 'murmur-32'`. Ensure your Node.js environment is at least 12.20.0, 14.13.1, or 16.0.0+.
breaking Version 0.2.0 changed the default string encoding from UCS-2 (UTF-16) to UTF-8. If your application was implicitly relying on UCS-2 encoding for string inputs prior to v0.2.0, hash outputs for the same string inputs will now differ.
Fix: If you need to maintain the exact hash values produced by older versions for string inputs, use the `array-buffer-from-string` package to explicitly convert your strings to UCS-2 encoded ArrayBuffers before passing them to `murmur32`. Otherwise, update any stored hash values or tests to reflect the new UTF-8 encoding behavior.

Install

npm install murmur-32 npm
yarn add murmur-32 yarn
pnpm add murmur-32 pnpm

Imports

murmur32
wrong:
```
const murmur32 = require('murmur-32')
```
correct:
```
import murmur32 from 'murmur-32'
```
The package converted to an ECMAScript module (ESM) in v1.0.0, dropping CommonJS support. Node.js version 12.20.0, 14.13.1, or >=16.0.0 is required.

Quickstart

Demonstrates how to compute a 32-bit MurmurHash3 for both string and ArrayBuffer inputs, and how to extract the integer hash value from the returned ArrayBuffer.

import murmur32 from 'murmur-32';

// Example 1: Hashing a string
const stringKey = 'hello world';
const stringHashBuffer = murmur32(stringKey);
const stringHashValue = new DataView(stringHashBuffer).getUint32(0, true); // Get 32-bit integer, little-endian

console.log(`Hash for "${stringKey}": ${stringHashValue.toString(16).padStart(8, '0')}`);

// Example 2: Hashing an ArrayBuffer
const arrayBufferKey = new TextEncoder().encode('another example').buffer;
const arrayBufferHashBuffer = murmur32(arrayBufferKey);
const arrayBufferHashValue = new DataView(arrayBufferHashBuffer).getUint32(0, true);

console.log(`Hash for "another example" (ArrayBuffer): ${arrayBufferHashValue.toString(16).padStart(8, '0')}`);

// The function returns an ArrayBuffer of 4 bytes (32-bit hash).
// You often need to convert it to an integer for practical use.

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