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).
- Full support for ECMAScript 2016 (ECMA-262 7th Edition)
- Sensible syntax tree format as standardized by ESTree project
- Optional tracking of syntax node location (index-based and line-column)
- Heavily tested
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"
}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.
| Script | Size | Esprima .NET | Esprima (Chrome) |
|---|---|---|---|
| underscore-1.5.2 | 43 KB | 2.4 ms | 3.1 ms |
| backbone-1.1.0 | 60 KB | 2.9 ms | 3.5 ms |
| mootools-1.4.5 | 163 KB | 18.7 ms | 16.2 ms |
| jquery-1.9.1 | 271 KB | 22.8 ms | 19.0 ms |
| yui-3.12.0 | 341 KB | 17.2 ms | 16.2 ms |
| jquery.mobile-1.4.2 | 456 K | 43.3 ms | 46.9 ms |
| angular-1.2.5 | 721 KB | 29.3 ms | 37.2 ms |