`repeat` — repeated-chunk pattern matcher

(no submodules)

Purpose

Finds every maximal substring composed of a repeating chunk (e.g. aaaa, abcabc, babababa) per Wheeler 2016 section 3.3. The chunk's strength is estimated by recursively running mostGuessableMatchSequence on the chunk itself with the same dictionary set — a password like passwordpassword gets the dictionary's rank-1 strength times the repeat-count factor.

Features

Detects single-character and multi-character repeats
Picks the longer of greedy and lazy chunk candidates so the matcher does not prefer aa four times over aaaa once
Recursive baseGuesses via mostGuessableMatchSequence
Carries the recursive baseMatches so consumers can inspect the chunk's own cover

Usage: Basic Example

import { repeatMatch } from "@suaveplan/password-strength/matchers/repeat";

const matches = repeatMatch("aaaa", {});
console.log(matches[0].baseToken); // "a"
console.log(matches[0].repeatCount); // 4

Usage: Advanced Example

import { repeatMatch } from "@suaveplan/password-strength/matchers/repeat";

const dicts = { passwords: new Map([["password", 1]]) };
const matches = repeatMatch("passwordpassword", dicts);
for (const m of matches) {
 console.log(m.baseToken, m.repeatCount, m.baseGuesses);
}

API Reference

repeatMatch(password: string, dictionaries: DictionarySet): RepeatMatch[]
- Returns every maximal repeat-of-chunk substring. The dictionary set is threaded into the chunk's recursive scoring so dictionary words appearing inside the chunk inherit their rank.

Implementation Notes

The matcher runs both a greedy and a lazy chunk regex from each candidate start position and picks whichever produces the longer overall repeat. Greedy finds the longest possible chunk that still repeats at least once; lazy finds the smallest. Picking the longer span avoids over-fragmenting a real repeat into two adjacent shorter ones with the same characters. The recursive scoring call uses the dictionary and sequence matchers — recursive keyboard or date matching inside a chunk is rare in practice and intentionally excluded for performance under the 200-character DoS guard.

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repeat — repeated-chunk pattern matcher