javascript - Object.create not supported in ie8

Question

I came across an issue with a plugin that uses object.create in jquery to create a date dropdown. I just noticed in IE 8 that it is throwing an error of:

SCRIPT438: Object doesn't support property or method 'create'

Here is the code:

var dropdateobj = Object.create(dropdatefuncs);
dropdateobj.create(options, this);
$.data(this, 'dropdate', dropdateobj);

What is a good work around for IE8 or more cross browser compatible?

Thanks in advance!

Answer 1

If you need Object.create, there are good chances you may need to rely on other es5 features as well. Therefore, in most cases the appropriate solution would be to use es5-shim.

However, if Object.create is the only thing you need and you only use it to purely setup the prototype chain, here's a lightweight poly-fill that doesn't support null as the first argument and doesn't support the second properties argument.

Here's the spec:

15.2.3.5 Object.create ( O [, Properties] )

The create function creates a new object with a specified prototype. When the create function is called, the following steps are taken:

If Type(O) is not Object or Null throw a TypeError exception.

Let obj be the result of creating a new object as if by the expression new Object() where Object is the standard built-in constructor with that name

Set the [[Prototype]] internal property of obj to O.

If the argument Properties is present and not undefined, add own properties to obj as if by calling the standard built-in function Object.defineProperties with arguments obj and Properties.

Return obj.

Here's the lightweight implementation:

if (!Object.create) {
    Object.create = function(o, properties) {
        if (typeof o !== 'object' && typeof o !== 'function') throw new TypeError('Object prototype may only be an Object: ' + o);
        else if (o === null) throw new Error("This browser's implementation of Object.create is a shim and doesn't support 'null' as the first argument.");

        if (typeof properties != 'undefined') throw new Error("This browser's implementation of Object.create is a shim and doesn't support a second argument.");

        function F() {}

        F.prototype = o;

        return new F();
    };
}