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helpers.js
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helpers.js
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// Shared empty constructor function to aid in prototype-chain creation.
var ctor = function(){};
// Helper function to correctly set up the prototype chain, for subclasses.
// Similar to `goog.inherits`, but uses a hash of prototype properties and
// class properties to be extended.
var inherits = function(parent, protoProps, staticProps) {
var child;
// The constructor function for the new subclass is either defined by you
// (the "constructor" property in your `extend` definition), or defaulted
// by us to simply call `super()`.
if (protoProps && protoProps.hasOwnProperty('constructor')) {
child = protoProps.constructor;
} else {
child = function(){ return parent.apply(this, arguments); };
}
// Inherit class (static) properties from parent.
_.extend(child, parent);
// Set the prototype chain to inherit from `parent`, without calling
// `parent`'s constructor function.
ctor.prototype = parent.prototype;
child.prototype = new ctor();
// Add prototype properties (instance properties) to the subclass,
// if supplied.
if (protoProps) _.extend(child.prototype, protoProps);
// Add static properties to the constructor function, if supplied.
if (staticProps) _.extend(child, staticProps);
// Correctly set child's `prototype.constructor`.
child.prototype.constructor = child;
// Set a convenience property in case the parent's prototype is needed later.
child.__super__ = parent.prototype;
return child;
};
var extend = function (protoProps, classProps) {
var child = inherits(this, protoProps, classProps);
child.extend = this.extend;
return child;
};
Container.extend = Events.extend = extend;