@randajan/regex-parser

Convert between JavaScript RegExp objects and their /pattern/flags string form — simple, safe and lightweight.

Install

npm i @randajan/regex-parser

Quick use

import { rgxToStr, strToRgx } from "@randajan/regex-parser";
// or: const { rgxToStr, strToRgx } = require("@randajan/regex-parser");

const re  = /hello\/world/i;
const str = rgxToStr(re);   // "/hello\\/world/i"
const re2 = strToRgx(str);  // ⇢ /hello\/world/i

API

rgxToStr(regexp) → string

Serialises a RegExp into /pattern/flags, escaping only those / that are not already escaped.

strToRgx(string, strict = false) → RegExp

• If the string matches /pattern/flags, parse it.
• Else
  • when strict = false (default) return a safe literal regex with the text escaped,
  • when strict = true throw SyntaxError.

strToRgx("/\d+/g");              // → /\d+/g
strToRgx("user.name?");           // → /user\.name\?/
strToRgx("user.name?", true);     // throws

Example round‑trip test

const originals = [/foo\/bar/i, /a+b*c?.(x|y)/g];

originals.forEach(r => {
  const r2 = strToRgx(rgxToStr(r));
  console.assert(r2.source === r.source && r2.flags === r.flags);
});

Why another regex helper?

• Zero dependencies – <1 kB min+gzip
• Predictable – strict mode prevents silent surprises
• Universal – Node ≥12 & all modern browsers

License

MIT © randajan