Log.js

// inspired from https://github.com/stacktracejs/stacktrace.js/blob/master/stacktrace.js
var Log = (function(){
  return {
    instrumentObj: instrumentObj
  };

  // This is working on my tests, do I made some "dangerous" things ?
  function instrumentObj(tag, obj){
    for(var i in obj){
      if(typeof obj[i] === 'function'){
        var fn = obj[i];
        var instrumented = function Log$$instrumented(){
          var jsonArgs = [];
          for(var j in arguments){
            jsonArgs.push(JSON.stringify(arguments[j]));
          }
          console.log(tag+'.'+i+'('+jsonArgs.join(', ')+')');
          return fn.apply(this, arguments);
        }
        instrumented.__riginalFn = fn;
        obj[i] = instrumented;
      }
    }
  }
})();

var myObj = {};
myObj.myFunction = function(arg){
  alert('Salut '+arg);
}
Log.instrumentObj('myObj', myObj);
myObj.myFunction('Toto');