krisk/Fuse

Fuse.js

Fuse.js is a lightweight, zero-dependency fuzzy-search library written in TypeScript. It works in the browser and on the server, and is designed for searching small-to-medium datasets on the client side where you can't rely on a dedicated search backend.

✨ What's New: Token Search

Multi-word fuzzy search with relevance ranking. Type "javascrpt paterns" and find "JavaScript Patterns" — typo tolerance, multiple words, and smart ranking all at once.

const fuse = new Fuse(docs, {
  useTokenSearch: true,
  keys: ['title', 'author', 'description']
})

fuse.search('javascrpt paterns')
// → [{ item: { title: 'JavaScript Patterns', ... } }]

See Token Search below for details.

Web Workers

Search large datasets without freezing the UI. FuseWorker splits your data across multiple Web Workers and searches in parallel — ~5x faster on 100K documents.

import { FuseWorker } from 'fuse.js/worker'

const fuse = new FuseWorker(docs, {
  keys: ['title', 'author', 'description']
})

const results = await fuse.search('query')
fuse.terminate()

Same options and results as Fuse — just async. Function-valued options (sortFn, getFn, keys[].getFn) aren't supported because functions can't be transferred to a worker; everything else carries over. See the Web Workers docs for the interactive demo and full API.

Installation

npm install fuse.js

yarn add fuse.js

Or include directly via CDN:

<script src="https://cdn.jsdelivr.net/npm/fuse.js/dist/fuse.min.mjs"></script>

Quick Start

import Fuse from 'fuse.js'

const books = [
  { title: "Old Man's War", author: 'John Scalzi' },
  { title: 'The Lock Artist', author: 'Steve Hamilton' },
  { title: 'HTML5', author: 'Remy Sharp' },
  { title: 'JavaScript: The Good Parts', author: 'Douglas Crockford' }
]

const fuse = new Fuse(books, {
  keys: ['title', 'author']
})

fuse.search('javscript')
// → [{ item: { title: 'JavaScript: The Good Parts', ... }, ... }]

Features

Fuzzy Search

The core of Fuse.js. Uses the Bitap algorithm for approximate string matching — handles typos, misspellings, and partial matches out of the box.

fuse.search('javscript')
// → [{ item: { title: 'JavaScript: The Good Parts', author: 'Douglas Crockford' } }]

Weighted Keys

Search across multiple fields with different importance levels. Title matches can rank higher than description matches.

const fuse = new Fuse(docs, {
  keys: [
    { name: 'title', weight: 2 },
    { name: 'description', weight: 1 }
  ]
})

Extended Search

Use operators for precise control: exact match (=), prefix (^), suffix (!), and more. Enable with useExtendedSearch: true.

const fuse = new Fuse(list, {
  useExtendedSearch: true,
  keys: ['title']
})

fuse.search('=exact match') // exact match
fuse.search('^prefix') // starts with
fuse.search('!term') // does not include

Object Query Syntax

Prefer a structured, self-documenting alternative to the magic characters? Express the same operators as an object. Unlike the string form, this needs no useExtendedSearch flag (the operators are unambiguous), autocompletes in TypeScript, and needs no quoting or escaping.

const fuse = new Fuse(list, { keys: ['title', 'author'] })

fuse.search({ title: { $startsWith: 'old' }, author: { $eq: 'Kay' } })

Each operator maps to a string equivalent:

Negate with $not, which wraps exactly one of $contains, $startsWith, or $endsWith:

fuse.search({ title: { $not: { $contains: 'draft' } } }) // === '!draft'
fuse.search({ title: { $not: { $startsWith: 'old' } } }) // === '!^old'
fuse.search({ title: { $not: { $endsWith: '.go' } } }) // === '!.go$'

Multiple operators on one field are AND-ed; use field-local $and / $or for more, and compose across fields with logical search:

// starts with "old" AND does not contain "draft"
fuse.search({ title: { $startsWith: 'old', $not: { $contains: 'draft' } } })

// title starts with "old" OR ends with "war"
fuse.search({ title: { $or: [{ $startsWith: 'old' }, { $endsWith: 'war' }] } })

Object queries return identical results to the equivalent string query, and validate strictly: unknown operators, empty or non-string values, and illegal nesting throw instead of silently degrading to a fuzzy search. Available in the full build. See the Extended Search docs for the full grammar.

Token Search

Splits multi-word queries into individual terms, fuzzy-matches each independently, and ranks results using BM25-style IDF weighting. Enable with useTokenSearch: true.

const fuse = new Fuse(docs, {
  useTokenSearch: true,
  keys: ['title', 'body']
})

fuse.search('express midleware rout')
// Finds "Express Middleware" and "Express Routing Guide" despite typos

• Typo tolerance per word — each term is fuzzy-matched independently
• Relevance ranking — rare terms are weighted higher than common ones
• Word order independent — "patterns javascript" and "javascript patterns" return identical results
• No query length limit — long multi-word queries work naturally since each term is searched separately
• AND or OR — tokenMatch: 'all' returns only records matching every word (filtering); the default 'any' matches any word
• Custom tokenizer — pass a regex or function via tokenize for tokens with internal punctuation (node.js, c++), or use Intl.Segmenter for CJK / Thai word segmentation. Unicode-aware by default

Available in the full build. See the Token Search docs for details and performance benchmarks.

Logical Search

Combine conditions with $and and $or for complex queries. Available in the full build.

fuse.search({
  $and: [{ title: 'javascript' }, { author: 'crockford' }]
})

Match Highlighting

Get character-level match indices for highlighting search results in your UI.

const fuse = new Fuse(list, {
  includeMatches: true,
  keys: ['title']
})

const result = fuse.search('javscript')
// result[0].matches[0].indices → [[0, 9]]

Single String Matching

Use Fuse.match() to fuzzy-match a pattern against a single string without creating an index. Useful for one-off comparisons or custom filtering.

const result = Fuse.match('javscript', 'JavaScript: The Good Parts')
// → { isMatch: true, score: 0.04, indices: [[0, 9]] }

Fuse.match() does not support useTokenSearch — token search requires corpus-level statistics (df, fieldCount) that a one-off string comparison can't provide. Passing useTokenSearch: true throws an explicit error. Use new Fuse(docs, { useTokenSearch: true }).search(query) for token-search behavior.

Dynamic Collections

Add and remove documents from a live index without rebuilding.

fuse.add({ title: 'New Book', author: 'New Author' })
fuse.remove((doc) => doc.title === 'Old Book')

Builds

Fuse.js ships in two variants:

Use the basic build if you only need fuzzy search and want the smallest bundle size.

Documentation

For the full API reference, configuration options, scoring theory, and interactive demos, visit fusejs.io.

Official ports

• fuse-swift: Swift port for iOS, macOS, tvOS, watchOS, visionOS, and Linux. Byte-equivalent results, idiomatic Swift API, syncs with each upstream release. Currently in 2.0.0-rc.1.

Supporting Fuse.js

• Become a backer or sponsor on GitHub
• Become a backer or sponsor on Patreon
• One-time donation via PayPal

Develop

See DEVELOPERS.md for setup, scripts, and project structure.

Contribute

See CONTRIBUTING.md for guidelines on issues and pull requests.