esprima-dotnet

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Esprima .NET (BSD license) is a .NET port of the esprima.org project. It is a standard-compliant ECMAScript parser (also popularly known as JavaScript).

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

API

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

A simple C# example:

var parser = new JavaScriptParser("const answer = 42");
var program = parser.ParseProgram();

Will return this when serialized in json:

{
    "type": "Program",
    "body": [
        {
            "type": "VariableDeclaration",
            "declarations": [
                {
                    "type": "VariableDeclarator",
                    "id": {
                        "type": "Identifier",
                        "name": "answer"
                    },
                    "init": {
                        "type": "Literal",
                        "value": 42,
                        "raw": "42"
                    }
                }
            ],
            "kind": "const"
        }
    ],
    "sourceType": "script"
}

Benchmarks

Here is a list of common JavaScript libraries and the time it takes to parse them, compared to the time it took for the same script using the original Esprima in Chrome.