Regulex, is a JavaScript Regular Expression Parser & Visualizer. It is designed to parse and visualize regular expressions.

Key features:

• It is written in pure JavaScript, so no backend is required.

• The visualization can be embedded on a user's site using an HTML iframe.

• It provides detailed error messages, often pinpointing the exact location of a syntax error.

• Regulex does not support octal escapes. According to the source, this is intentional, because ECMAScript strict mode does not allow octal escapes in strings. Regulex will treat DecimalEscapes as back references and throw an error if they are invalid or appear in a character set.

Regulex also has an API that allows users to parse a regular expression into an Abstract Syntax Tree (AST) and to visualize it using Raphael. The API includes functions to parse regular expressions, visualize them, and log errors.

The application can be installed using npm for Node.js. It also provides instructions for local browser builds.