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.

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📦 Installation

npm install merge-regex

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🚀 Usage

import { mergeRegex } from "merge-regex";

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

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🛠️ 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.

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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.

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📋 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)/

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📖 License

MIT