45 lines
2.3 KiB
Markdown
45 lines
2.3 KiB
Markdown
[](https://www.npmjs.com/package/esprima)
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[](https://www.npmjs.com/package/esprima)
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[](https://travis-ci.org/jquery/esprima)
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[](https://codecov.io/github/jquery/esprima)
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**Esprima** ([esprima.org](http://esprima.org), BSD license) is a high performance,
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standard-compliant [ECMAScript](http://www.ecma-international.org/publications/standards/Ecma-262.htm)
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parser written in ECMAScript (also popularly known as
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[JavaScript](https://en.wikipedia.org/wiki/JavaScript)).
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Esprima is created and maintained by [Ariya Hidayat](https://twitter.com/ariyahidayat),
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with the help of [many contributors](https://github.com/jquery/esprima/contributors).
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### Features
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- Full support for ECMAScript 2016 ([ECMA-262 7th Edition](http://www.ecma-international.org/publications/standards/Ecma-262.htm))
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- Sensible [syntax tree format](https://github.com/estree/estree/blob/master/es5.md) as standardized by [ESTree project](https://github.com/estree/estree)
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- Experimental support for [JSX](https://facebook.github.io/jsx/), a syntax extension for [React](https://facebook.github.io/react/)
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- Optional tracking of syntax node location (index-based and line-column)
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- [Heavily tested](http://esprima.org/test/ci.html) (~1300 [unit tests](https://github.com/jquery/esprima/tree/master/test/fixtures) with [full code coverage](https://codecov.io/github/jquery/esprima))
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### API
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Esprima can be used to perform [lexical analysis](https://en.wikipedia.org/wiki/Lexical_analysis) (tokenization) or [syntactic analysis](https://en.wikipedia.org/wiki/Parsing) (parsing) of a JavaScript program.
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A simple example on Node.js REPL:
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```javascript
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> var esprima = require('esprima');
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> var program = 'const answer = 42';
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> esprima.tokenize(program);
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[ { type: 'Keyword', value: 'const' },
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{ type: 'Identifier', value: 'answer' },
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{ type: 'Punctuator', value: '=' },
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{ type: 'Numeric', value: '42' } ]
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> esprima.parse(program);
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{ type: 'Program',
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body:
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[ { type: 'VariableDeclaration',
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declarations: [Object],
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kind: 'const' } ],
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sourceType: 'script' }
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```
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