How to handle lack of JavaScript Object.bind() method in IE 8
I am writing a bit of JavaScript that uses the Object.bind
method.
funcabc = function(x, y, z){
this.myx = x;
this.playUB = function(w) {
if ( this.myx === null ) {
// do blah blah
return;
}
// do other stuff
};
this.play = this.playUB.bind(this);
};
Since I develop in WinXP with Firefox and sometimes test in Win7 with IE 9 or 10, I did not notice or pay attention to the fact that IE8 and below do not support bind
.
This particular script does not use the canvas, so I'm a little hesitant to write off all IE 8 users.
Is there a standard work-around?
I'm getting around sort of okay in JavaScript, but I'm still a bit of a noob. So forgive me if the solution is totally obvious.
There is a good compatability script on this page: https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Function/bind
Just copy and paste it into your script.
EDIT: placing the script below for clarity.
if (!Function.prototype.bind) {
Function.prototype.bind = function(oThis) {
if (typeof this !== 'function') {
// closest thing possible to the ECMAScript 5
// internal IsCallable function
throw new TypeError('Function.prototype.bind - what is trying to be bound is not callable');
}
var aArgs = Array.prototype.slice.call(arguments, 1),
fToBind = this,
fNOP = function() {},
fBound = function() {
return fToBind.apply(this instanceof fNOP && oThis
? this
: oThis,
aArgs.concat(Array.prototype.slice.call(arguments)));
};
fNOP.prototype = this.prototype;
fBound.prototype = new fNOP();
return fBound;
};
}
The best solution could be to install Modernizr.
Modernizr tells you whether the current browser has this feature natively implemented or not and it provides a script loader so you can pull in polyfills to backfill functionality in old browsers.
Here is the link to generate your modernizr custom version:
http://modernizr.com/download/#-teststyles-testprop-testallprops-hasevent-prefixes-domprefixes
Function.prototype.bind isn’t supported in Internet Explorer 8 and below. Compatibility chart here: http://kangax.github.io/es5-compat-table/
Mozilla Developer Network provide this alternative for older browsers that don't implemented .bind() natively:
if (!Function.prototype.bind) {
Function.prototype.bind = function (oThis) {
if (typeof this !== "function") {
// closest thing possible to the ECMAScript 5 internal IsCallable function
throw new TypeError("Function.prototype.bind - what is trying to be bound is not callable");
}
var aArgs = Array.prototype.slice.call(arguments, 1),
fToBind = this,
fNOP = function () {},
fBound = function () {
return fToBind.apply(this instanceof fNOP && oThis
? this
: oThis,
aArgs.concat(Array.prototype.slice.call(arguments)));
};
fNOP.prototype = this.prototype;
fBound.prototype = new fNOP();
return fBound;
};
}