Regexpu: Enhancing JavaScript Regular Expressions for Better Performance

Welcome to the world of regexpu! A powerful tool designed to work with JavaScript regular expressions, enabling seamless Unicode support and optimizations. Whether you’re a novice or a seasoned developer, understanding the capabilities of regexpu can greatly enhance your coding efficiencies. In this guide, we will delve into the useful APIs of regexpu with examples showcasing their functionalities.

API Examples

1. rewritePattern

The rewritePattern function transforms any regular expression with Unicode into a working pattern supported by JavaScript.

  const rewritePattern = require('regexpu-core').rewritePattern;
  const pattern = 'a.b';
  const result = rewritePattern(pattern);
  console.log(result); // Outputs: "a.b"

2. transformPattern

The transformPattern function improves the runtime behavior using specific transformations.

  const transformPattern = require('regexpu-core').transformPattern;
  const pattern = '\\p{Script=Greek}';
  const transformed = transformPattern(pattern, {
    unicodePropertyEscape: true
  });
  console.log(transformed);
  // Outputs: "[\u0370-\u03FF\u1F00-\u1FFF]"

Application Example with Introduction APIs

Let’s walk through a practical example to cement your understanding. Assume you are creating an application that validates usernames to comply with Unicode character requirements using regexpu.

  const { rewritePattern, transformPattern } = require('regexpu-core');

  const usernamePattern = '[\\p{L}\\p{N}_]{3,15}';
  const transformedPattern = transformPattern(rewritePattern(usernamePattern, {
    unicodePropertyEscape: true
  }), {
    unicodePropertyEscape: true
  });

  function validateUsername(username) {
    const regex = new RegExp(transformedPattern);
    return regex.test(username);
  }

  console.log(validateUsername('user_123')); // true
  console.log(validateUsername('usér_name')); // true
  console.log(validateUsername('us#r_name')); // false

As demonstrated, regexpu provides the necessary tools to transform complex Unicode patterns into manageable regular expressions, ensuring compatibility and enhancing performance.

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