kudzu

Fast evaluation on ESTree-compatible ASTs

Features

• Comprehensive tests
• Fully asynchronous API and internals
• Esprima and Cherow compatible
• ECMA 3 and IE8 compatible
• ESNext support

Install

npm install esprima-eval

Usage

var esEval   = require('esprima-eval'),
    esprima  = require('esprima');

var ast   = esprima.parseScript(' ... '),
    scope = new esEval.Scope(globals);

scope.on('get', function () {
  // supports custom scope data handlers
});

scope.on('ConditionalExpression', function () {
  // supports custom lexical node handlers
});

scope.walk(ast, function (returnValue) {
  // done
});

Support

Runtime

• [ ] Strict mode
• [ ] Error handling
• [ ] Error skipping/resolution
• [x] Protected global objects/prototypes

Globals

• [ ] Array
• [x] Function
• [x] Object
• [ ] Date
• [ ] Number
• [ ] RegExp
• [ ] String
• [ ] Proxy
• [ ] Symbol
• [ ] Math

Scope

• [x] Scope chain
• [x] Function scope (var)
• [x] Block scope (let)

Operations

• [x] Binary (&, |, ^)
• [x] Mathematical (+, -, /, *, %)
• [x] Increment before (++i, --i)
• [ ] Increment after (i++, i--)
• [ ] Add assignment
• [ ] Subtract assignment
• [ ] Multiply assignment
• [ ] Divide assignment
• [ ] typeof

Conditionals

• [x] And/or
• [x] Strict/non-strict equality
• [x] <, >, <=, >=
• [x] instanceof
• [x] If statements

Loops

• [x] For loops
• [ ] While loops
• [ ] break
• [ ] continue
• [ ] return

Functions

• [x] Function declarations
• [x] Anonymous closures
• [ ] Arrow functions
• [ ] Async functions
• [ ] Spread operator
• [ ] Object identity

Proxies

• [ ] Proxy constructor
• [ ] Has/get/set/delete property
• [ ] Get/set property descriptor
• [ ] Get/set prototype
• [ ] Apply

Promises

• [ ] Promise constructor
• [ ] Promise.then
• [ ] Promise.catch

Symbols

Errors

• [ ] Error constructor
• [ ] Stack traces
• [ ] Try/catch

Prior Art

https://www.npmjs.com/package/esper.js https://www.npmjs.com/package/sandboxr https://github.com/NeilFraser/JS-Interpreter https://github.com/mozilla/narcissus/