Creating prototype chains in JavaScript (ES-5)
I'm trying to create a function that creates an object with a prototype chain, like this:
something = object(proto1, proto2, proto3);
// Lookup order is something -> proto1 -> proto2 -> proto3 -> Object.prototype
I'd to wrap the given prototypes to override their own lookup chains (so they can be reused), and want to do so with minimal copying/inner attribute wrapping.
Is there any feature in Javas开发者_如何学编程cript/ECMAScript 5 that can be used to override all attribute accesses on an object? Something akin to __getattribute__(self, attrname)
in Python? If not, how should I go about this? Am I forced to just clone the object's properties (with Object.hasOwnProperty()
)?
JavaScript has prototypes, so could use a construct like:
// Small utility function
function Object.extend(obj, properties) {
for (var i in properties) {
obj[i] = properties[i];
}
return obj;
}
// Create a subclass of Object
function Class3() {}
Class3.prototype = proto3;
// Create a subclass of Class3
function Class2() {}
Class2.prototype = new Class3();
Object.extend(Class2.prototype, proto2);
// Create a subclass of Class2
function Class1() {}
Class1.prototype = new Class2();
Object.extend(Class1.prototype, proto1);
// Instantiate an object whose prototype chain is proto1, proto2, proto3
var something = new Class1();
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