Babel Parser (formerly Babylon)

Babel Parser, previously known as Babylon, is a highly configurable JavaScript parser that generates an Abstract Syntax Tree (AST) from source code. It is a fundamental component of the Babel toolchain, used for transpiling modern JavaScript into compatible versions. Currently stable at version 7.x, it receives frequent updates, including beta releases for upcoming ECMAScript features. Its key differentiators include a pluggable architecture supporting a wide array of experimental and standard JavaScript syntax extensions like JSX, Flow, and TypeScript, as well as new proposals like nullish coalescing, optional chaining, and the pipeline operator. The parser offers both `parse` for full programs and `parseExpression` for single expressions, along with options for comment attachment and error recovery, providing detailed AST output based on the ESTree spec with Babel's specific deviations.