merge-regex

A lightweight utility to merge multiple regular expressions into a single composite regex, with support for pattern deduplication, anchor preservation, global anchors, and configurable output.

📦 Installation

npm install merge-regex

🚀 Usage

import { mergeRegex } from "merge-regex";

const regex = mergeRegex([/^foo$/, /^bar$/]);
console.log(regex);
// Output: /(?:^foo$|^bar$)/

🛠️ API

mergeRegex(patterns: RegExp[], options?: MergeRegexOptions): RegExp

Merge multiple regex patterns into a single composite regex.

Parameters

| Name | Type | Default | Description | | -------- | ------------------- | -------- | ------------------------------------- | | patterns | RegExp[] | Required | List of regular expressions to merge. | | options | MergeRegexOptions | {} | Optional configuration object. |

MergeRegexOptions

| Option | Type | Default | Description | | ----------------------- | ------- | ------- | ---------------------------------------------------------------------------------------- | | preserveAnchors | boolean | true | If true, keeps ^ and $ within each branch. If false, removes anchors before merging. | | mergeAnchors | boolean | false | If true (and preserveAnchors is false), lifts common anchors to the entire pattern. | | deduplicate | boolean | true | If true, removes duplicate regex patterns. | | wrapNonCapturingGroup | boolean | false | If true, always wraps the result in a non-capturing group, even for a single pattern. |

📋 Examples

Preserve Anchors (default)

mergeRegex([/^foo$/, /^bar$/]);
// Output: /(?:^foo$|^bar$)/

Remove Anchors & Merge Globally

mergeRegex([/^foo$/, /^bar$/], {
  preserveAnchors: false,
  mergeAnchors: true,
});
// Output: /^(?:foo|bar)$/

No Deduplication

mergeRegex([/foo/, /foo/], { deduplicate: false });
// Output: /(?:foo|foo)/

📖 License

MIT