bindObjEvt(): wrap functions in order to use other contexts and additional arguments

bindObjEvt.js

/**
  * Wraps a function. It enables passing a new context and new arguments.
  * @param func The actual function
  * @param obj The context ('this' object) to pass to 'func'. If null is given, 'func' gets the context forwarded.
  * @param args The arguments 'func' should receive. These will be added to the list of already passed arguments.
  * @param addCtx Specifies whether the originally passed context should be added as an argument.
  * @return A wrapper function.
  *
  * @author ComFreek
  * @license Public Domain. Attribution optional.
  */
function bindObjEvt(func, obj, args, addCtx) {
    if (args === null) {
        args = [];
    }
    return function () {
        var newArgs = Array.prototype.slice.call(arguments).concat(args);
        if (addCtx) {
            newArgs.push(this);
        }
        func.apply(obj || this, newArgs);
    };
}

examples.js

var obj = {
  initListeners: function () {
    // #btn, #btn2, #btn3 are buttons.
    document.getElementById("btn").addEventListener("click", bindObjEvt(this.clicked1, this));
    document.getElementById("btn2").addEventListener("click", bindObjEvt(this.clicked2, this, ["Hello", "World!"]));
    document.getElementById("btn3").addEventListener("click", bindObjEvt(this.clicked2, this, ["Hello", "World!"], true));
  },

  // this = obj
  // evt = event object
  clicked1: function (evt) {
  },

  // this = obj
  // evt = event object
  // var1 = Hello, var2 = World!
  clicked2: function (evt, var1, var2) {
  },

  // this = obj
  // evt = event object
  // ctx = HTMLButtonElement object
  clicked3: function (evt, ctx) {
  }
};

// another example
var func = bindObjEvt(function () {
    // convert arguments object to an array
    var argumentsAsArray = Array.prototype.slice.call(arguments);
    // will alert "C, D, B, A, [object Window]"
    alert(argumentsAsArray);
  },
  document, ["A", "B"], true
);

func("C", "D");