Constructor and metadata

Compile a reusable dictionary from strings or entries with application data.

Create a matcher

import AhoCorasick from 'modern-ahocorasick'

const matcher = new AhoCorasick([
  'cat',
  { pattern: 'dog', data: { id: 7 } },
], { boundary: 'none' })
matcher.search('dog')[0]?.data // { id: 7 }

Strings and metadata objects can be mixed. patternIndex refers to the original input position, so duplicates remain distinguishable. Input patterns are captured at construction; metadata retains its original reference. Mutating inputs or returned match objects does not change compiled matching state.

An empty list [] is valid and never matches. An empty pattern '' throws RangeError naming its input index. Invalid runtime arguments throw TypeError.

Options and types

The signature is new AhoCorasick<T>(patterns: readonly PatternInput<T>[], options?: MatcherOptions). The optional boundary rule defaults to none.

import type { Match, PatternInput } from 'modern-ahocorasick'
import AhoCorasick from 'modern-ahocorasick'

const patterns: PatternInput<{ id: number }>[] = [{ pattern: 'cat', data: { id: 1 } }]
const matches: Match<{ id: number }>[] = new AhoCorasick(patterns).search('cat')

See Boundary rules.

State ownership

The goto table, failure links, output links and builder are implementation details. No gotoFn, failure, output, or public trace() API exists in v3. The visualizer uses a repository-internal integration, not a supported consumer API.

See Dynamic dictionaries.