RegExpStructor

Build regular expressions via a fluent api

Highlights

• Describe your matcher in a human readable way
• Fluent api to build your regular expressions
• Make maintainable complex regular expressions
• Immutable for maximum reuseablity: All methods return a fresh RegExpstructor. No implicit mutation of any internals that could lead to unexpected results
• Composable: Build more complex expressions from your simple RegExpstructors. Use combinators like ReStructor.seq(...RegExpstructors) or ReStructor.or(...RegExpstructors) to combine your matchers.
• No useless non-capture group wrapping in the output (the final Regexp will be as performant and readable as possible)

Getting started

Install with

npm i regexpstructor

or with yarn

yarn add regexpstructor

Usage

// ES module import:
import ReStructor from "regexpstructor";

// or in commonjs:
const ReStructor = require("regexpstructor");

/**
 * @example building a UUID regexp
 */
const hexChar = ReStructor().charOfRanges(["0", "9"], ["a", "f"]);

// tests for [0-9a-f]{8} - eg. "a019bc3f"
const digitBlock_8 = hexChar.repeatExactly(8);

// tests for [0-9a-f]{4} - eg. "bc3f"
const digitBlock_4 = hexChar.repeatExactly(4);

// uuid looks like this: "a019bc3f-1234-5678-9abc-def012345678"
const uuid = digitBlock_8
  .then("-")
  .then(
    // 3 times a 4-digit blocks, each followed by a dash
    digitBlock_4.then("-").repeatExactly(3)
  )
  .then(
    // block of size 12
    hexChar.repeatExactly(12)
  )
  .withAnyCase() // make case insensitive
  .searchOneLine(); // single line search

// compile the uuid reStructor into a regExp
const regex = uuid.compile();

// use it:
regex.test("a019bc3f-1234-5678-9abc-def012345678"); // result: true

// print it:
console.log(regex); /* logs: /[0-9a-f]{8}-(?:[0-9a-f]{4}-){3}[0-9a-f]{12}/gi */