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Using Object.create in IE7 -- question on copying objects vs pointers to objects

in Using jQuery • 11 years ago

I have two objects, 'Loaded' and 'Current'. I wanted to make 'Current' a copy of 'Loaded' initially, but I found that if I just set 'Current = Loaded', that 'Current' was acting as a pointer to 'Loaded'. Any changes I made to 'Current' updated 'Loaded' also. I read online that the way to do it was to use 'Current = Object.create(Loaded)', which worked perfectly.

However, now I'm doing my browser testing -- I have to support IE7+ -- and in IE7, that line gives me the error "Object doesn't support property or method 'create'".

Is there an IE7-friendly way to do this?

Any help would be greatly appreciated!!

Replies(2)

jsclark

Re: Using Object.create in IE7 -- question on copying objects vs pointers to objects

11 years ago

Check this out:

http://stackoverflow.com/questions/2766057/what-is-happening-in-crockfords-object-creation-technique

You should be able to do:

if( Object.create === undefined ) {
Object.create = function( o ) {
function F(){}
F.prototype = o;
return new F();
};
}

This is only really relevant if your objects are truly objects in the OO sense; i.e. they have a prototype and you instantiate them with 'new', etc.

If you're dealing with simple objects, e.g. { one: 1, two: 2 }, then I would recommend using $.extend() instead, as it will actually make a new object and copy the properties of your existing object to it, rather than using prototypical inheritance to make a faux copy.

The problem with using Object.create() is that unless you change the property of the copied object, if the value of a property on the parent changes, the value on the child will too. Take a look at this to see what I mean: http://jsfiddle.net/Fpj84/

More info on Object.create(): https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Object/create

tslatt

Re: Using Object.create in IE7 -- question on copying objects vs pointers to objects

11 years ago

Thanks! I was able to use extend for my purposes -- and it worked in IE7.

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