regex-recursion

• Edge case fix for capturing groups with transfer markers.

• Support recursion of Regex+ emulation groups (with hidden and transfer markers) and subpatterns that contain them.

• Don't include duplicated captures in result arrays when using the subclass option.

• Allow numbered backreferences if recursed subpatterns don't contain captures.

• Fix for recursion by number.

• Added support for multiple, non-overlapping recursions in the same pattern.

• Added support for subpattern recursion by group number.
• Added d.ts type file.
• Added sourcemap for browser bundle.
• Slightly faster to determine that a pattern doesn't contain recursion.
• Fix: Throws for certain invalid recursion depth values.
• Fix: For some invalid cases with duplicate recursion, was generating invalid regex syntax.

Breaking changes

• Removed the rregex template tag previously provided as sugar. Instead of e.g. rregex`…`, import the base regex library separately and use regex({plugins: [recursion]})`…`.
• Changed the global name in the regex-recursion.min.js browser bundle from Regex.ext to Regex.plugins.

Improvements

• Updated documentation and tests to use the regex v4.0.0 plugin API.

Fixes

• Fixed a syntax error when using a named backreference within recursion that references a group outside of the recursive subpattern.

If desired, you can recreate the rregex tag from previous versions:

import {regex} from 'regex';
import {recursion} from 'regex-recursion';

function rregex(first, ...values) {
  const plugins = (first?.plugins || []).concat(recursion);
  // Given a template
  if (Array.isArray(first?.raw)) {
    return regex({plugins})(first, ...values);
  // Given flags
  } else if ((typeof first === 'string' || first === undefined) && !values.length) {
    return regex({flags: first, plugins});
  // Given an options object
  } else if ({}.toString.call(first) === '[object Object]' && !values.length) {
    return regex({...first, plugins});
  }
  throw new Error(`Unexpected arguments: ${JSON.stringify([first, ...values])}`);
}

• Updated the base regex package to v3.1.0.
• Documentation improvements.
• Fixed an edge case where lookbehind could be mistaken for named capture.

• Changed the capture/backreference depth suffix from $rN to _$N.
• Fixed recursion with patterns that use atomic groups.
• Avoids incorrect handling when recursion is used with numbered backreferences from interpolated RegExp instances, by throwing a descriptive error.
• Fixed an issue with unnamed capturing groups when implicit flag n is disabled.