Jinter is a JavaScript interpreter written in CoffeeScript.

The project's purpose is purely educational. The evaluator does not cover the whole JavaScript specification but it covers enough of the language to evaluate itself.

Language constructs supported:

• literals (numbers, strings, booleans and null)
• the binary +, -, * operators for strings, numbers and objects with valueOf/toString
• ===, !==, ==, !=, <, <=
• short circuited &&, ||
• the unary operators +, -, !, typeof
• if expressions and statements
• while/for statements
• vars, the = operator
• the postfix ++ operator
• objects, getters and setters
• function expressions/declarations
• the new operator and this
• prototypes, prototype chains, the non-standard __proto__
• methods on primitives
• Arrays (pop, push, slice, join, toString, forEach, map, filter, reduce)
• Maps (get, has, set, forEach)
• Function::apply, Function::call
• Object.create, Object.keys
• the global isNaN, parseInt, parseFloat, Number, Boolean, String

Check out the full list of test cases here. In addition, all test cases pass when Jinter evaluates them while being evaluated by Jinter.