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Esprima is a high performance, standard-compliant ECMAScript parser written in ECMAScript (also popularly known as JavaScript). It is capable of parsing JavaScript code to produce an abstract syntax tree (AST), which can be used for various purposes such as static analysis, code instrumentation, and transformation.
Parsing JavaScript Code
This feature allows you to parse a string of JavaScript code and obtain an abstract syntax tree (AST) that represents the structure of the code.
const esprima = require('esprima');
const program = 'const answer = 42;';
const ast = esprima.parseScript(program);
Syntax Tree Analysis
Once you have the AST, you can analyze it to extract information about the code, such as variable names, function declarations, and more.
const esprima = require('esprima');
const program = 'const answer = 42;';
const ast = esprima.parseScript(program);
console.log(ast.body[0].declarations[0].id.name); // 'answer'
Tokenization
Esprima can also be used to tokenize JavaScript code, breaking it down into its lexical components (tokens) such as keywords, identifiers, literals, and operators.
const esprima = require('esprima');
const program = 'const answer = 42;';
const tokens = esprima.tokenize(program);
console.log(tokens);
Acorn is a tiny, fast JavaScript parser, also producing an AST. It is similar to Esprima in terms of functionality but focuses on being smaller and more modular.
Cherow is a very fast, standards-compliant, self-hosted JavaScript parser with error recovery. It compares to Esprima in terms of compliance and performance but also offers better error handling and recovery options.
Esprima (esprima.org) 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 runs on web browsers (IE 6+, Firefox 1+, Safari 3+, Chrome 1+, Konqueror 4.6+, Opera 8+) as well as Node.js.
Esprima is blazing fast (see the benchmark suite). It is up to 3x faster than UglifyJS v1 and it is still competitive with the new generation of fast parsers.
Esprima serves as the basis for many popular JavaScript development tools:
Follow @Esprima on Twitter to get the development updates. Feedback and contribution are welcomed!
Copyright (C) 2012, 2011 Ariya Hidayat and other contributors.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
FAQs
ECMAScript parsing infrastructure for multipurpose analysis
The npm package esprima receives a total of 28,332,163 weekly downloads. As such, esprima popularity was classified as popular.
We found that esprima demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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