regjsparser

What is regjsparser?

The regjsparser npm package is a JavaScript library that parses regular expressions into an abstract syntax tree (AST). This can be useful for analyzing, transforming, or generating regular expressions programmatically.

What are regjsparser's main functionalities?

Parsing Regular Expressions

This feature allows you to parse a regular expression into an abstract syntax tree (AST). The AST can then be used for further analysis or transformation.

const regjsparser = require('regjsparser');
const regex = /abc/;
const ast = regjsparser.parse(regex);
console.log(JSON.stringify(ast, null, 2));

Handling Unicode

This feature allows you to parse regular expressions that include Unicode characters. The 'u' flag is used to indicate that the regular expression should be treated as a sequence of Unicode code points.

const regjsparser = require('regjsparser');
const regex = /\u{1F600}/u;
const ast = regjsparser.parse(regex);
console.log(JSON.stringify(ast, null, 2));

Error Handling

This feature provides error handling capabilities when parsing invalid regular expressions. It throws an error with a descriptive message if the regular expression is not valid.

const regjsparser = require('regjsparser');
try {
  const regex = /[a-z/;
  const ast = regjsparser.parse(regex);
} catch (e) {
  console.error('Parsing error:', e.message);
}

Other packages similar to regjsparser

regexpp

regexpp is a regular expression parser for ECMAScript. It parses regular expressions into an AST and provides utilities for traversing and analyzing the AST. Compared to regjsparser, regexpp offers more detailed error messages and supports the latest ECMAScript features.

regexp-tree

regexp-tree is a regular expression processing library that includes a parser, transformer, and optimizer. It parses regular expressions into an AST and provides tools for transforming and optimizing them. Unlike regjsparser, regexp-tree focuses on providing a complete suite of tools for working with regular expressions.

regex-parser

regex-parser is a simple library for parsing regular expressions into an AST. It is less feature-rich compared to regjsparser and focuses on providing a minimalistic approach to parsing regular expressions.

README

RegJSParser

Parsing the JavaScript's RegExp in JavaScript.

Installation

npm install regjsparser

Usage

var parse = require('regjsparser').parse;

var parseTree = parse('^a'); // /^a/
console.log(parseTree);

// Toggle on/off additional features:
var parseTree = parse('^a', '', {
  // SEE: https://github.com/jviereck/regjsparser/pull/78
  unicodePropertyEscape: true,

  // SEE: https://github.com/jviereck/regjsparser/pull/83
  namedGroups: true,

  // SEE: https://github.com/jviereck/regjsparser/pull/89
  lookbehind: true
});
console.log(parseTree);

Testing

To run the tests, run the following command:

npm test

To create a new reference file, execute…

node test/update-fixtures.js

…from the repo top directory.