jison‑lex is a JavaScript lexical‑analyzer generator that reads a lexer specification (in JSON or Bison‑style `.l` format) and produces a runnable JS lexer, primarily used as the front‑end for the jison parser generator. It can be used from the command line or programmatically to embed custom tokenizers in Node or browser‑based projects. The tool targets developers building compilers, interpreters, or any application needing fast, customizable tokenisation in JavaScript.