jquery/esprima

ECMAScript parsing infrastructure for multipurpose analysis

Source code at GitHub http://esprima.org

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Esprima (esprima.org, 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.

Features

Full support for ECMAScript 2019 (ECMA-262 10th Edition)
Sensible syntax tree format as standardized by ESTree project
Experimental support for JSX, a syntax extension for React
Optional tracking of syntax node location (index-based and line-column)
Heavily tested (~1600 unit tests with full code coverage)

API

Esprima can be used to perform lexical analysis (tokenization) or syntactic analysis (parsing) of a JavaScript program.

A simple example on Node.js REPL:

> var esprima = require('esprima');
> var program = 'const answer = 42';

> esprima.tokenize(program);
[ { type: 'Keyword', value: 'const' },
  { type: 'Identifier', value: 'answer' },
  { type: 'Punctuator', value: '=' },
  { type: 'Numeric', value: '42' } ]

> esprima.parseScript(program);
{ type: 'Program',
  body:
   [ { type: 'VariableDeclaration',
       declarations: [Object],
       kind: 'const' } ],
  sourceType: 'script' }

For more information, please read the complete documentation.