bind all implementation

bindAll.js

var obj = {
  id: 1,
  whoami: function() {
    return this.id;
  }
};

function callExternally(callback) {
  this.id = 99;
  return callback();
}

function myBindAll() {
  var args = Array.prototype.slice.call(arguments);
  var context = args.shift();
  _(args).each(function(func) {
    var oldF = context[func];
    context[func] = function() {
      console.log("patched function");
      return oldF.apply(context, arguments);
    };
  });
}

console.log(obj.id);
console.log(callExternally(obj.whoami));
console.log(myBindAll(obj, "whoami"));
console.log(callExternally(obj.whoami));