ahocorasick-ts/index.js

ahocorasick implemention

class TrieNode {
    matched;
    child;
    failure;
    constructor(root) {
        this.matched = [];
        this.child = {};
        if (root) {
            this.failure = root;
        }
        else {
            this.failure = this;
        }
    }
}
export class AhoCorasick {
    trie;
    constructor(keyword) {
        this.trie = new TrieNode();
        keyword.forEach(s => {
            let cur = this.trie;
            for (const ch of s) {
                if (!(ch in cur.child)) {
                    cur.child[ch] = new TrieNode(this.trie);
                }
                cur = cur.child[ch];
            }
            cur.matched.push(s);
        });
        const queue = [];
        for (const ch in this.trie.child) {
            queue.push(this.trie.child[ch]);
        }
        while (queue.length > 0) {
            const cur = queue.shift();
            for (const ch in cur.child) {
                queue.push(cur.child[ch]);
                let f = cur.failure;
                while (f !== this.trie && !(ch in f.child)) {
                    f = f.failure;
                }
                if (ch in f.child) {
                    cur.child[ch].failure = f.child[ch];
                    cur.child[ch].matched.push(...cur.failure.matched);
                }
                else {
                    cur.child[ch].failure = this.trie;
                }
            }
        }
    }
    search(key) {
        let cur = this.trie;
        const res = [];
        key.split("").forEach((ch, i) => {
            while (cur !== this.trie && !(ch in cur.child)) {
                cur = cur.failure;
            }
            if (!(ch in cur.child)) {
                return;
            }
            cur = cur.child[ch];
            if (cur.matched.length) {
                res.push({
                    end: i,
                    keys: cur.matched,
                });
            }
        });
        return res;
    }
}