Facebook-specific fork of the esprima project

Esprima (, BSD license) is a high performance, standard-compliant ECMAScript parser written in ECMAScript (also popularly known as JavaScript). Esprima is created and maintained by Ariya Hidayat, with the help of many contributors.

Esprima-FB is a fork of the Harmony branch of Esprima that implements JSX specification on top of ECMAScript syntax.

In order to follow semver rules and keep reference to original Esprima versions at the same time, we left 3 digits of each version part to refer to upstream harmony branch. We then take the most significant digit.

Example: 4001.3001.0000-dev-harmony-fb aligns with 1.1.0-dev-harmony (aka 001.001.000-dev-harmony) in upstream, with our own changes on top.

Esprima-FB serves as a building block for JSX language tools and transpiler implementations (such as React or JSXDOM).

Esprima-FB runs on many popular web browsers, as well as other ECMAScript platforms such as Rhino and Node.js.

For more information on original Esprima, check the web site