How to check whether one class is inhereted of another class?

I'm using Ext4...

How to check whether one class is inherited of another class?

for example:

Ext.define("A", {});
Ext.define("B", { extend: "A" });
Ext.define("C", { extend: "B" });

var a = Ext.create("A");
var c = Ext.create("C");

I need something like this: c 开发者_高级运维instanceof a

???

Thanks

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(Based on @troelskn 's comment)

http://jsfiddle.net/miriam/ugQHB/

c instanceof A

returns true.

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You can use isXtype method. See docs here: Ext.AbstractComponent