Simple comparison of several compile-to-javascript languages, including: CoffeeScript, Dart, Haxe, and TypeScript.

build.log

/usr/bin/time dart2js -ooutput/dart.js source/simple.dart
        3.30 real         3.01 user         0.25 sys
/usr/bin/time tsc --out output/typescript.js --sourcemap source/simple.ts
        0.98 real         0.86 user         0.10 sys
/usr/bin/time coffee -p source/simple.coffee > output/coffee.js
        0.18 real         0.14 user         0.02 sys
/usr/bin/time haxe -cp source/ -main Simple -js output/haxe.js --dead-code-elimination --js-modern -debug
        0.05 real         0.04 user         0.01 sys
/usr/bin/time jsx --executable web --enable-source-map --output output/jsx.js source/simple.jsx
        0.42 real         0.35 user         0.05 sys

coffee.js

(function() {
  var Simple;

  Simple = (function() {

    function Simple(name) {
      this.name = name != null ? name : "default";
    }

    Simple.prototype.greet = function(who) {
      return "Greetings " + who + ", I'm " + this.name + "!";
    };

    Simple.main = function() {
      var s;
      s = new Simple("Flynn");
      return console.log(s.greet("Program"));
    };

    return Simple;

  })();

  Simple.main();

}).call(this);

dart.js

// Generated by dart2js, the Dart to JavaScript compiler.
// The code supports the following hooks:
// dartPrint(message)   - if this function is defined it is called
//                        instead of the Dart [print] method.
// dartMainRunner(main) - if this function is defined, the Dart [main]
//                        method will not be invoked directly.
//                        Instead, a closure that will invoke [main] is
//                        passed to [dartMainRunner].
function Isolate() {}
init();

var $$ = {};
var $ = Isolate.$isolateProperties;
$$.StringBufferImpl = {"":
 ["_buffer", "_length"],
 "super": "Object",
 get$length: function() {
  return this._length;
},
 isEmpty$0: function() {
  return this._length === 0;
},
 add$1: function(obj) {
  var str = $.toString(obj);
  if (str == null || $.isEmpty(str) === true)
    return this;
  $.add$1(this._buffer, str);
  this._length = $.add(this._length, $.get$length(str));
  return this;
},
 clear$0: function() {
  this._buffer = $.ListImplementation_List(null);
  this._length = 0;
  return this;
},
 toString$0: function() {
  if ($.get$length(this._buffer) === 0)
    return '';
  if ($.get$length(this._buffer) === 1)
    return $.index(this._buffer, 0);
  var result = $.StringImplementation_concatAll(this._buffer);
  $.clear(this._buffer);
  $.add$1(this._buffer, result);
  return result;
},
 StringBufferImpl$1: function(content$) {
  this.clear$0();
  this.add$1(content$);
}
};

$$.ArgumentError = {"":
 ["message"],
 "super": "Object",
 toString$0: function() {
  var t1 = this.message;
  if (!(t1 == null))
    return 'Illegal argument(s): ' + $.S(t1);
  return 'Illegal argument(s)';
}
};

$$.IndexOutOfRangeException = {"":
 ["_value"],
 "super": "Object",
 toString$0: function() {
  return 'IndexOutOfRangeException: ' + $.S(this._value);
}
};

$$.NullPointerException = {"":
 ["functionName", "arguments"],
 "super": "Object",
 toString$0: function() {
  var t1 = this.functionName;
  if (t1 == null)
    return this.get$exceptionName();
  else
    return $.S(this.get$exceptionName()) + ' : method: \'' + $.S(t1) + '\'\n' + 'Receiver: null\n' + 'Arguments: ' + $.S(this.arguments);
},
 get$exceptionName: function() {
  return 'NullPointerException';
}
};

$$.NoMoreElementsException = {"":
 [],
 "super": "Object",
 toString$0: function() {
  return 'NoMoreElementsException';
}
};

$$.UnsupportedOperationException = {"":
 ["_message"],
 "super": "Object",
 toString$0: function() {
  return 'UnsupportedOperationException: ' + this._message;
}
};

$$.Object = {"":
 [],
 "super": "",
 operator$eq$1: function(other) {
  return this === other;
},
 toString$0: function() {
  return $.Primitives_objectToString(this);
}
};

$$.ListIterator = {"":
 ["i", "list"],
 "super": "Object",
 hasNext$0: function() {
  return this.i < this.list.length;
},
 next$0: function() {
  if (this.hasNext$0() !== true)
    throw $.$$throw($.NoMoreElementsException$());
  var value = this.list[this.i];
  this.i = this.i + 1;
  return value;
}
};

$$.Closure = {"":
 [],
 "super": "Object",
 toString$0: function() {
  return 'Closure';
}
};

$$.Simple = {"":
 ["name"],
 "super": "Object",
 greet$1: function(who) {
  return 'Greetings ' + who + ', I\'m ' + this.name + '!';
}
};

$$.Maps__emitMap_anon = {"":
 ["result_3", "box_0", "visiting_2"],
 "super": "Closure",
 call$2: function(k, v) {
  var t1 = this.box_0;
  if (t1.first_1 !== true)
    $.add$1(this.result_3, ', ');
  t1.first_1 = false;
  t1 = this.result_3;
  var t2 = this.visiting_2;
  $.Collections__emitObject(k, t1, t2);
  $.add$1(t1, ': ');
  $.Collections__emitObject(v, t1, t2);
}
};

$.S = function(value) {
  var res = $.toString(value);
  if (!(typeof res === 'string'))
    throw $.$$throw($.ArgumentError$(value));
  return res;
};

$.StringBuffer_StringBuffer = function(content$) {
  return $.StringBufferImpl$(content$);
};

$.gt$slow = function(a, b) {
  if ($.checkNumbers(a, b))
    return a > b;
  return a.operator$gt$1(b);
};

$.checkGrowable = function(list, reason) {
  if (!!(list.fixed$length))
    throw $.$$throw($.UnsupportedOperationException$(reason));
};

$.$$throw = function(ex) {
  if (ex == null)
    ex = $.CTC;
  var jsError = new Error();
  jsError.name = ex;
  jsError.description = ex;
  jsError.dartException = ex;
  jsError.toString = $.toStringWrapper.call$0;
  throw jsError;
};

$.iterator = function(receiver) {
  if ($.isJsArray(receiver))
    return $.ListIterator$(receiver);
  return receiver.iterator$0();
};

$.ArgumentError$ = function(message) {
  return new $.ArgumentError(message);
};

$.NullPointerException$ = function(functionName, arguments$) {
  return new $.NullPointerException(functionName, arguments$);
};

$.eqB = function(a, b) {
  if (a == null)
    return b == null;
  if (b == null)
    return false;
  if (typeof a === "object")
    if (!!a.operator$eq$1)
      return a.operator$eq$1(b) === true;
  return a === b;
};

$.add$1 = function(receiver, value) {
  if ($.isJsArray(receiver)) {
    $.checkGrowable(receiver, 'add');
    receiver.push(value);
    return;
  }
  return receiver.add$1(value);
};

$.Collections__emitCollection = function(c, result, visiting) {
  $.add$1(visiting, c);
  var isList = typeof c === 'object' && c !== null && (c.constructor === Array || !!c.is$List);
  $.add$1(result, isList ? '[' : '{');
  for (var t1 = $.iterator(c), first = true; t1.hasNext$0() === true;) {
    var t2 = t1.next$0();
    if (!first)
      $.add$1(result, ', ');
    $.Collections__emitObject(t2, result, visiting);
    first = false;
  }
  $.add$1(result, isList ? ']' : '}');
  $.removeLast(visiting);
};

$.Primitives_newList = function(length$) {
  if (length$ == null)
    return new Array();
  if (!(typeof length$ === 'number' && Math.floor(length$) === length$) || length$ < 0)
    throw $.$$throw($.ArgumentError$(length$));
  var result = new Array(length$);
  result.fixed$length = true;
  return result;
};

$.set$length = function(receiver, newLength) {
  if ($.isJsArray(receiver)) {
    $.checkNull(newLength);
    if (newLength < 0)
      throw $.$$throw($.IndexOutOfRangeException$(newLength));
    $.checkGrowable(receiver, 'set length');
    receiver.length = newLength;
  } else
    receiver.set$length(newLength);
  return newLength;
};

$.Primitives_printString = function(string) {
  if (typeof dartPrint == "function") {
    dartPrint(string);
    return;
  }
  if (typeof window == "object") {
    if (typeof console == "object")
      console.log(string);
    return;
  }
  if (typeof print == "function") {
    print(string);
    return;
  }
  throw 'Unable to print message: ' + String(string);
};

$.toStringWrapper = function() {
  return $.toString(this.dartException);
};

$.checkNum = function(value) {
  if (!(typeof value === 'number')) {
    $.checkNull(value);
    throw $.$$throw($.ArgumentError$(value));
  }
  return value;
};

$.get$length = function(receiver) {
  if (typeof receiver === 'string' || $.isJsArray(receiver))
    return receiver.length;
  else
    return receiver.get$length();
};

$.constructorNameFallback = function(object) {
  var constructor$ = object.constructor;
  if (typeof(constructor$) === 'function') {
    var name$ = constructor$.name;
    if (typeof name$ === 'string')
      var t1 = !(name$ === '') && !(name$ === 'Object') && !(name$ === 'Function.prototype');
    else
      t1 = false;
    if (t1)
      return name$;
  }
  var string = Object.prototype.toString.call(object);
  return string.substring(8, string.length - 1);
};

$.toString = function(value) {
  if (typeof value == "object" && value !== null)
    if ($.isJsArray(value))
      return $.Collections_collectionToString(value);
    else
      return value.toString$0();
  if (value === 0 && (1 / value) < 0)
    return '-0.0';
  if (value == null)
    return 'null';
  if (typeof value == "function")
    return 'Closure';
  return String(value);
};

$.IndexOutOfRangeException$ = function(_value) {
  return new $.IndexOutOfRangeException(_value);
};

$.index = function(a, index) {
  if (typeof a == "string" || a.constructor === Array) {
    var key = index >>> 0;
    if (key === index && key < a.length)
      return a[key];
  }
  return $.index$slow(a, index);
};

$.substring$2 = function(receiver, startIndex, endIndex) {
  $.checkNum(startIndex);
  var length$ = receiver.length;
  if (endIndex == null)
    endIndex = length$;
  $.checkNum(endIndex);
  if (startIndex < 0)
    throw $.$$throw($.IndexOutOfRangeException$(startIndex));
  if ($.gtB(startIndex, endIndex))
    throw $.$$throw($.IndexOutOfRangeException$(startIndex));
  if ($.gtB(endIndex, length$))
    throw $.$$throw($.IndexOutOfRangeException$(endIndex));
  return $.substringUnchecked(receiver, startIndex, endIndex);
};

$.StringBufferImpl$ = function(content$) {
  var t1 = new $.StringBufferImpl(null, null);
  t1.StringBufferImpl$1(content$);
  return t1;
};

$.UnsupportedOperationException$ = function(_message) {
  return new $.UnsupportedOperationException(_message);
};

$.removeLast = function(receiver) {
  if ($.isJsArray(receiver)) {
    $.checkGrowable(receiver, 'removeLast');
    if ($.get$length(receiver) === 0)
      throw $.$$throw($.IndexOutOfRangeException$(-1));
    return receiver.pop();
  }
  return receiver.removeLast$0();
};

$.gtB = function(a, b) {
  return typeof a === 'number' && typeof b === 'number' ? a > b : $.gt$slow(a, b) === true;
};

$.Simple$ = function(name$) {
  return new $.Simple(name$);
};

$.ltB = function(a, b) {
  return typeof a === 'number' && typeof b === 'number' ? a < b : $.lt$slow(a, b) === true;
};

$.isJsArray = function(value) {
  return !(value == null) && value.constructor === Array;
};

$.StringImplementation_concatAll = function(strings) {
  return $.stringJoinUnchecked($.StringImplementation__toJsStringArray(strings), '');
};

$.substring$1 = function(receiver, startIndex) {
  if (!(typeof receiver === 'string'))
    return receiver.substring$1(startIndex);
  return $.substring$2(receiver, startIndex, null);
};

$.clear = function(receiver) {
  if (!$.isJsArray(receiver))
    return receiver.clear$0();
  $.set$length(receiver, 0);
};

$.checkNull = function(object) {
  if (object == null)
    throw $.$$throw($.NullPointerException$(null, $.CTC0));
  return object;
};

$.charCodeAt = function(receiver, index) {
  if (typeof receiver === 'string') {
    if (index < 0)
      throw $.$$throw($.IndexOutOfRangeException$(index));
    if (index >= receiver.length)
      throw $.$$throw($.IndexOutOfRangeException$(index));
    return receiver.charCodeAt(index);
  } else
    return receiver.charCodeAt$1(index);
};

$.Primitives_objectToString = function(object) {
  return 'Instance of \'' + $.S($.Primitives_objectTypeName(object)) + '\'';
};

$.Primitives_objectTypeName = function(object) {
  var name$ = $.constructorNameFallback(object);
  if ($.eqB(name$, 'Object')) {
    var decompiled = String(object.constructor).match(/^\s*function\s*(\S*)\s*\(/)[1];
    if (typeof decompiled === 'string')
      name$ = decompiled;
  }
  return $.charCodeAt(name$, 0) === 36 ? $.substring$1(name$, 1) : name$;
};

$.lt$slow = function(a, b) {
  if ($.checkNumbers(a, b))
    return a < b;
  return a.operator$lt$1(b);
};

$.Collections__emitObject = function(o, result, visiting) {
  if (typeof o === 'object' && o !== null && (o.constructor === Array || !!o.is$Collection))
    if ($.Collections__containsRef(visiting, o))
      $.add$1(result, typeof o === 'object' && o !== null && (o.constructor === Array || !!o.is$List) ? '[...]' : '{...}');
    else
      $.Collections__emitCollection(o, result, visiting);
  else if (typeof o === 'object' && o !== null && !!o.is$Map)
    if ($.Collections__containsRef(visiting, o))
      $.add$1(result, '{...}');
    else
      $.Maps__emitMap(o, result, visiting);
  else
    $.add$1(result, o);
};

$.Maps__emitMap = function(m, result, visiting) {
  var t1 = {};
  $.add$1(visiting, m);
  $.add$1(result, '{');
  t1.first_1 = true;
  m.forEach$1(new $.Maps__emitMap_anon(result, t1, visiting));
  $.add$1(result, '}');
  $.removeLast(visiting);
};

$.checkNumbers = function(a, b) {
  if (typeof a === 'number')
    if (typeof b === 'number')
      return true;
    else {
      $.checkNull(b);
      throw $.$$throw($.ArgumentError$(b));
    }
  return false;
};

$.main = function() {
  $.print($.Simple$('Flyn').greet$1('Program'));
};

$.StringImplementation__toJsStringArray = function(strings) {
  if (typeof strings !== 'object' || strings === null || (strings.constructor !== Array || !!strings.immutable$list) && !strings.is$JavaScriptIndexingBehavior)
    return $.StringImplementation__toJsStringArray$bailout(1, strings);
  $.checkNull(strings);
  var length$ = strings.length;
  if ($.isJsArray(strings)) {
    for (var i = 0; i < length$; ++i) {
      if (i >= strings.length)
        throw $.ioore(i);
      var string = strings[i];
      $.checkNull(string);
      if (!(typeof string === 'string'))
        throw $.$$throw($.ArgumentError$(string));
    }
    var array = strings;
  } else {
    array = $.ListImplementation_List(length$);
    for (i = 0; i < length$; ++i) {
      if (i >= strings.length)
        throw $.ioore(i);
      string = strings[i];
      $.checkNull(string);
      if (!(typeof string === 'string'))
        throw $.$$throw($.ArgumentError$(string));
      array[i] = string;
    }
  }
  return array;
};

$.ListImplementation_List = function(length$) {
  return $.Primitives_newList(length$);
};

$.index$slow = function(a, index) {
  if (typeof a === 'string' || $.isJsArray(a)) {
    if (!(typeof index === 'number' && Math.floor(index) === index)) {
      if (!(typeof index === 'number'))
        throw $.$$throw($.ArgumentError$(index));
      if (!($.truncate(index) === index))
        throw $.$$throw($.ArgumentError$(index));
    }
    if ($.ltB(index, 0) || $.geB(index, $.get$length(a)))
      throw $.$$throw($.IndexOutOfRangeException$(index));
    return a[index];
  }
  return a.operator$index$1(index);
};

$.add = function(a, b) {
  return typeof a === 'number' && typeof b === 'number' ? a + b : $.add$slow(a, b);
};

$.truncate = function(receiver) {
  return receiver < 0 ? $.ceil(receiver) : $.floor(receiver);
};

$.print = function(object) {
  if (typeof object === 'string')
    $.Primitives_printString(object);
  else
    $.Primitives_printString($.toString(object));
};

$.ceil = function(receiver) {
  return Math.ceil(receiver);
};

$.ListIterator$ = function(list) {
  return new $.ListIterator(0, list);
};

$.Collections__containsRef = function(c, ref) {
  for (var t1 = $.iterator(c); t1.hasNext$0() === true;) {
    var t2 = t1.next$0();
    if (t2 == null ? ref == null : t2 === ref)
      return true;
  }
  return false;
};

$.Collections_collectionToString = function(c) {
  var result = $.StringBuffer_StringBuffer('');
  $.Collections__emitCollection(c, result, $.ListImplementation_List(null));
  return $.toString(result);
};

$.NoMoreElementsException$ = function() {
  return new $.NoMoreElementsException();
};

$.isEmpty = function(receiver) {
  if (typeof receiver === 'string' || $.isJsArray(receiver))
    return receiver.length === 0;
  return receiver.isEmpty$0();
};

$.stringJoinUnchecked = function(array, separator) {
  return array.join(separator);
};

$.geB = function(a, b) {
  return typeof a === 'number' && typeof b === 'number' ? a >= b : $.ge$slow(a, b) === true;
};

$.ge$slow = function(a, b) {
  if ($.checkNumbers(a, b))
    return a >= b;
  return a.operator$ge$1(b);
};

$.substringUnchecked = function(receiver, startIndex, endIndex) {
  return receiver.substring(startIndex, endIndex);
};

$.ioore = function(index) {
  throw $.$$throw($.IndexOutOfRangeException$(index));
};

$.floor = function(receiver) {
  return Math.floor(receiver);
};

$.add$slow = function(a, b) {
  if ($.checkNumbers(a, b))
    return a + b;
  return a.operator$add$1(b);
};

$.StringImplementation__toJsStringArray$bailout = function(state0, strings) {
  $.checkNull(strings);
  var length$ = $.get$length(strings);
  if ($.isJsArray(strings)) {
    for (var i = 0; $.ltB(i, length$); ++i) {
      var string = $.index(strings, i);
      $.checkNull(string);
      if (!(typeof string === 'string'))
        throw $.$$throw($.ArgumentError$(string));
    }
    var array = strings;
  } else {
    array = $.ListImplementation_List(length$);
    for (i = 0; $.ltB(i, length$); ++i) {
      string = $.index(strings, i);
      $.checkNull(string);
      if (!(typeof string === 'string'))
        throw $.$$throw($.ArgumentError$(string));
      if (i >= array.length)
        throw $.ioore(i);
      array[i] = string;
    }
  }
  return array;
};

$.toStringWrapper.call$0 = $.toStringWrapper;
$.toStringWrapper.$name = "toStringWrapper";
Isolate.$finishClasses($$);
$$ = {};
Isolate.makeConstantList = function(list) {
  list.immutable$list = true;
  list.fixed$length = true;
  return list;
};
$.CTC0 = Isolate.makeConstantList([]);
$.CTC1 = null;
$.CTC = new Isolate.$isolateProperties.NullPointerException(null, Isolate.$isolateProperties.CTC0);
$.Primitives_DOLLAR_CHAR_VALUE = 36;
var $ = null;
Isolate.$finishClasses($$);
$$ = {};
Isolate = Isolate.$finishIsolateConstructor(Isolate);
var $ = new Isolate();

//
// BEGIN invoke [main].
//
if (typeof document != 'undefined' && document.readyState != 'complete') {
  document.addEventListener('readystatechange', function () {
    if (document.readyState == 'complete') {
      if (typeof dartMainRunner == 'function') {
        dartMainRunner(function() { $.main(); });
      } else {
        $.main();
      }
    }
  }, false);
} else {
  if (typeof dartMainRunner == 'function') {
    dartMainRunner(function() { $.main(); });
  } else {
    $.main();
  }
}
//
// END invoke [main].
//

function init() {
Isolate.$isolateProperties = {};
Isolate.$defineClass = function(cls, fields, prototype) {
  var generateGetterSetter =   function(field, prototype) {
    var len = field.length;
    var lastChar = field[len - 1];
    var needsGetter = lastChar == '?' || lastChar == '=';
    var needsSetter = lastChar == '!' || lastChar == '=';
    if (needsGetter || needsSetter) field = field.substring(0, len - 1);
    if (needsGetter) {
      var getterString = "return this." + field + ";";
        prototype["get$" + field] = new Function(getterString);
    }
    if (needsSetter) {
      var setterString = "this." + field + " = v;";
      prototype["set$" + field] = new Function("v", setterString);
    }
    return field;
  };
  var constructor;
  if (typeof fields == 'function') {
    constructor = fields;
  } else {
    var str = "function " + cls + "(";
    var body = "";
    for (var i = 0; i < fields.length; i++) {
      if (i != 0) str += ", ";
      var field = fields[i];
      field = generateGetterSetter(field, prototype);
      str += field;
      body += "this." + field + " = " + field + ";\n";
    }
    str += ") {" + body + "}\n";
    str += "return " + cls + ";";
    constructor = new Function(str)();
  }
  constructor.prototype = prototype;
  return constructor;
};
var supportsProto = false;
var tmp = Isolate.$defineClass('c', ['f?'], {}).prototype;
if (tmp.__proto__) {
  tmp.__proto__ = {};
  if (typeof tmp.get$f !== "undefined") supportsProto = true;
}
Isolate.$pendingClasses = {};
Isolate.$finishClasses = function(collectedClasses) {
  var hasOwnProperty = Object.prototype.hasOwnProperty;
  for (var cls in collectedClasses) {
    if (hasOwnProperty.call(collectedClasses, cls)) {
      var desc = collectedClasses[cls];
      Isolate.$isolateProperties[cls] = Isolate.$defineClass(cls, desc[''], desc);
      if (desc['super'] !== "") Isolate.$pendingClasses[cls] = desc['super'];
    }
  }
  var pendingClasses = Isolate.$pendingClasses;
  Isolate.$pendingClasses = {};
  var finishedClasses = {};
  function finishClass(cls) {
    var hasOwnProperty = Object.prototype.hasOwnProperty;
    if (hasOwnProperty.call(finishedClasses, cls)) return;
    finishedClasses[cls] = true;
    var superclass = pendingClasses[cls];
    if (!superclass) return;
    finishClass(superclass);
    var constructor = Isolate.$isolateProperties[cls];
    var superConstructor = Isolate.$isolateProperties[superclass];
    var prototype = constructor.prototype;
    if (supportsProto) {
      prototype.__proto__ = superConstructor.prototype;
      prototype.constructor = constructor;
    } else {
      function tmp() {};
      tmp.prototype = superConstructor.prototype;
      var newPrototype = new tmp();
      constructor.prototype = newPrototype;
      newPrototype.constructor = constructor;
      for (var member in prototype) {
        if (member == '' || member == 'super') continue;
        if (hasOwnProperty.call(prototype, member)) {
          newPrototype[member] = prototype[member];
        }
      }
    }
  }
  for (var cls in pendingClasses) finishClass(cls);
};
Isolate.$finishIsolateConstructor = function(oldIsolate) {
  var isolateProperties = oldIsolate.$isolateProperties;
  var isolatePrototype = oldIsolate.prototype;
  var str = "{\n";
  str += "var properties = Isolate.$isolateProperties;\n";
  for (var staticName in isolateProperties) {
    if (Object.prototype.hasOwnProperty.call(isolateProperties, staticName)) {
      str += "this." + staticName + "= properties." + staticName + ";\n";
    }
  }
  str += "}\n";
  var newIsolate = new Function(str);
  newIsolate.prototype = isolatePrototype;
  isolatePrototype.constructor = newIsolate;
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};
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}

haxe.js

(function () { "use strict";
var Simple = function(name) {
	this.name = name;
};
Simple.main = function() {
	var s = new Simple("Flynn");
	console.log(s.greet("Program"));
}
Simple.prototype = {
	greet: function(who) {
		return "Greetings " + who + ", I'm " + this.name + "!";
	}
}
var Std = function() { }
Simple.main();
})();

//@ sourceMappingURL=haxe.js.map

haxe.js.map

{
"version":3,
"file":"haxe.js",
"sourceRoot":"file://",
"sources":["/Users/darthapo/Projects/Gists/compile-to-js-comparisions/source/simple.hx"],
"names":[],
"mappings":";SAMC,MAA0B;CACxB,EAAW;;cAON,HAAgB;CACrB,EAAe,QAAW;CAC1B,WAAO,XAAQ;;;OANjB,OAA2B;OAClB,AAAC,JAAW,AAAG,AAAO,AAAI;;;;;;;"
}

jsx.js

var JSX = {};
(function () {

/**
 * copies the implementations from source interface to target
 */
function $__jsx_merge_interface(target, source) {
	for (var k in source.prototype)
		if (source.prototype.hasOwnProperty(k))
			target.prototype[k] = source.prototype[k];
}

/**
 * defers the initialization of the property
 */
function $__jsx_lazy_init(obj, prop, func) {
	function reset(obj, prop, value) {
		delete obj[prop];
		obj[prop] = value;
		return value;
	}

	Object.defineProperty(obj, prop, {
		get: function () {
			return reset(obj, prop, func());
		},
		set: function (v) {
			reset(obj, prop, v);
		},
		enumerable: true,
		configurable: true
	});
}

/**
 * sideeffect().a /= b
 */
function $__jsx_div_assign(obj, prop, divisor) {
	return obj[prop] = (obj[prop] / divisor) | 0;
}

/*
 * global functions called by JSX
 * (enamed so that they do not conflict with local variable names)
 */
var $__jsx_parseInt = parseInt;
var $__jsx_parseFloat = parseFloat;
var $__jsx_isNaN = isNaN;
var $__jsx_isFinite = isFinite;

var $__jsx_encodeURIComponent = encodeURIComponent;
var $__jsx_decodeURIComponent = decodeURIComponent;
var $__jsx_encodeURI = encodeURI;
var $__jsx_decodeURI = decodeURI;

var $__jsx_ObjectToString = Object.prototype.toString;
var $__jsx_ObjectHasOwnProperty = Object.prototype.hasOwnProperty;

/*
 * profiler object, initialized afterwards
 */
function $__jsx_profiler() {
}

/*
 * public interface to JSX code
 */
JSX.require = function (path) {
	var m = $__jsx_classMap[path];
	return m !== undefined ? m : null;
};

JSX.profilerIsRunning = function () {
	return $__jsx_profiler.getResults != null;
};

JSX.getProfileResults = function () {
	return ($__jsx_profiler.getResults || function () { return {}; })();
};

JSX.postProfileResults = function (url) {
	if ($__jsx_profiler.postResults == null)
		throw new Error("profiler has not been turned on");
	return $__jsx_profiler.postResults(url);
};

JSX.resetProfileResults = function () {
	if ($__jsx_profiler.resetResults == null)
		throw new Error("profiler has not been turned on");
	return $__jsx_profiler.resetResults();
};
/**
 * class Simple extends Object
 * @constructor
 */
function Simple() {
}

Simple.prototype = new Object;
/**
 * @constructor
 * @param {!string} name
 */
function Simple$S(name) {
	this.name = name;
};

Simple$S.prototype = new Simple;

/**
 * @param {!string} who
 * @return {!string}
 */
Simple.prototype.greet$S = function (who) {
	return "Greetings " + who + ", I'm " + this.name + "!";
};

/**
 * class _Main extends Object
 * @constructor
 */
function _Main() {
}

_Main.prototype = new Object;
/**
 * @constructor
 */
function _Main$() {
};

_Main$.prototype = new _Main;

/**
 * @param {Array.<undefined|!string>} args
 */
_Main.main$AS = function (args) {
	/** @type {Simple} */
	var s;
	s = new Simple$S("Flynn");
	console.log(s.greet$S("Program"));
};

var _Main$main$AS = _Main.main$AS;

var $__jsx_classMap = {
	"source/simple.jsx": {
		Simple: Simple,
		Simple$S: Simple$S,
		_Main: _Main,
		_Main$: _Main$
	}
};


/**
 * launches _Main.main(:string[]):void invoked by jsx --run|--executable
 */
JSX.runMain = function (sourceFile, args) {
	var module = JSX.require(sourceFile);

	if (! module._Main) {
		throw new Error("entry point _Main not found in " + sourceFile);
	}
	if (! module._Main.main$AS) {
		throw new Error("entry point _Main.main(:string[]):void not found in " + sourceFile);
	}
	module._Main.main$AS(args);
};

/**
 * launches _Test#test*():void invoked by jsx --test
 */
JSX.runTests = function (sourceFile, tests) {
	var module = JSX.require(sourceFile);
	var testClass = module._Test$;

	if (!testClass) return; // skip if there's no test class

	if(tests.length === 0) {
		var p = testClass.prototype;
		for (var m in p) {
			if (p[m] instanceof Function
				&& /^test.*[$]$/.test(m)) {
				tests.push(m);
			}
		}
	}
	else { // set as process arguments
		tests = tests.map(function (name) {
			return name + "$"; // mangle for function test*():void
		});
	}

	var testCase = new testClass();

	if (testCase.beforeClass$AS != null)
		testCase.beforeClass$AS(tests);

	for (var i = 0; i < tests.length; ++i) {
		(function (method) {
			if (method in testCase) {
				testCase.run$SF$V$(method, function() { testCase[method](); });
			}
			else {
				throw new ReferenceError("No such test method: " + method);
			}
		}(tests[i]));
	}

	if (testCase.afterClass$ != null)
		testCase.afterClass$();
};
/**
 * call a function on load/DOMContentLoaded
 */
function $__jsx_onload (event) {
	window.removeEventListener("load", $__jsx_onload);
	document.removeEventListener("DOMContentLoaded", $__jsx_onload);
	JSX.runMain("source/simple.jsx", [])
}

window.addEventListener("load", $__jsx_onload);
document.addEventListener("DOMContentLoaded", $__jsx_onload);

})();

//@ sourceMappingURL=output/jsx.js.mapping

jsx.js.mapping

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Makefile

.PHONY: compile

time=/usr/bin/time

compile: dart typescript coffeescript haxe jsx

dart:
	$(time) dart2js -ooutput/dart.js source/simple.dart

typescript:
	$(time) tsc --out output/typescript.js --sourcemap source/simple.ts

coffeescript:
	$(time) coffee -p source/simple.coffee > output/coffee.js

haxe:
	$(time) haxe -cp source/ -main Simple -js output/haxe.js --dead-code-elimination --js-modern -debug

jsx:
	$(time) jsx --executable web --enable-source-map --output output/jsx.js source/simple.jsx

simple.coffee

class Simple

  constructor: (@name = "default") ->

  greet: (who) ->
    "Greetings #{ who }, I'm #{ @name }!"

  @main: ->
    s= new Simple "Flynn"
    console.log s.greet "Program"

Simple.main()

simple.dart

class Simple {

  String name;

  Simple(this.name);

  greet(who) => "Greetings $who, I'm $name!";
}

main() {
  var s= new Simple('Flyn');

  print( s.greet('Program'));  
}

simple.hx

using Std;

class Simple {

  var name:String;

  function new(name:String) {
    this.name= name;
  }

  function greet(who:String) {
    return "Greetings $who, I'm $name!".format();
  }

  static function main() {
    var s:Simple = new Simple("Flynn");
    trace( s.greet("Program") );
  }
}

simple.jsx

class Simple {
  
  var name:string;

  function constructor(name:string) {
    this.name = name;
  }

  function greet(who:string): string {
    return "Greetings "+ who +", I'm "+ this.name +"!";
  }

}

class _Main {
  static function main(args:string[]):void {
    var s= new Simple("Flynn");
    log s.greet("Program");
  }
}

simple.ts

class Simple {
  
  constructor(public name: string) {}

  greet(who: string) {
    return "Greetings "+ who +", I'm "+ this.name +"!";
  }

  static main() {
    var s = new Simple('Flynn');
    console.log(s.greet("Program"));  
  }

}

Simple.main()

typescript.js

var Simple = (function () {
    function Simple(name) {
        this.name = name;
    }
    Simple.prototype.greet = function (who) {
        return "Greetings " + who + ", I'm " + this.name + "!";
    };
    Simple.main = function main() {
        var s = new Simple('Flynn');
        console.log(s.greet("Program"));
    }
    return Simple;
})();
Simple.main();
//@ sourceMappingURL=typescript.js.map

typescript.js.map

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FYI, there is a new Dart compiler being written [1] which will emit more idiomatic JavaScript. Perhaps someone can run it for comparison?

[1] https://github.com/dart-lang/dev_compiler

Looks like Bob Nystrom posted the new compiler's output:

https://gist.github.com/munificent/bde42b3d02c563fb4a9c