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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  "names": ["int","_length","bool","StringBuffer","obj","str","_buffer","List","String","StringImplementation","StringBufferImpl","clear","add","message","_value","functionName","exceptionName","arguments","_message","Primitives","i","list","T","hasNext","NoMoreElementsException","greet","name","result","Collections","value","ArgumentError","factory","gt$slow","checkNumbers","a","checkGrowable","UnsupportedOperationException","$throw","iterator","isJsArray","ListIterator","receiver","add$1","static","visiting","_emitObject","set$length","checkNull","IndexOutOfRangeException","toStringWrapper","JS","checkNum","get$length","string","toString","index","index$slow","substring$2","substringUnchecked","removeLast","gtB","Simple","ltB","lt$slow","stringJoinUnchecked","_toJsStringArray","substring$1","NullPointerException","charCodeAt","objectTypeName","constructorNameFallback","_containsRef","_emitCollection","Maps","m","main","print","s","strings","add$slow","truncate","object","ceil","isEmpty","geB","ge$slow","ioore","floor"]
}

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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typescript's output is the best.
Dart's the ugliest.

In Dart's defense, the definition of the language isn't meant to completely mirror Javascript. While the designers try to keep Dart's behavior as in-line with JS as possible, they implement a lot of different behavior that they believe make it an easier language to work with (such as range checking on array access). The downside of that is the generated javascript is uglier.

thanks for sharing information in such precise manner

Coming from an ActionScript 3.0 background, I think TypeScript and Haxe are the two most attractive options here, especially looking at the minimal JS generated by their compilers. But given that Haxe can compile to other platforms / devices, I wonder if it's really worth the time to learn TypeScript.

Haxe compile times also smoke the competition.

Ugliest output and 3 second compile, Dart, really? Google's losing it. =P =)

Test needs to be updated. Newest TypeScript compiles faster, Haxe 3 has new shorter syntax

Using Std isn't needed in the Haxe script. Output will be cleaner without.

Anyway this comparision is useless: what about the real world when you have tens or hundreds of classes?

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