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backbone.memento.js
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backbone.memento.js
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// Backbone.Memento v0.1.1
//
// Copyright (C)2011 Derick Bailey, Muted Solutions, LLC
// Distributed Under MIT Liscene
//
// Documentation and Full Licence Availabe at:
// http://github.com/derickbailey/backbone.memento
// ----------------------------
// Backbone.Memento
// ----------------------------
Backbone.Memento = (function(model){
var attributeStack = new Array();
function getRemovedAttrDiff(newAttrs, oldAttrs){
var removedAttrs = [];
for (var attr in oldAttrs){
if (oldAttrs.hasOwnProperty(attr)){
if (!newAttrs.hasOwnProperty(attr)){
removedAttrs.push(attr);
}
}
}
return removedAttrs;
}
function removeAttributes(model, attrsToRemove){
for (var index in attrsToRemove){
attr = removedAttrs[index];
model.unset(attr);
}
}
return {
version: "0.1.1",
push: function(){
attributeStack.push(model.toJSON());
},
pop: function(){
var last = attributeStack.length-1;
if (last < 0)
return null;
//get the previous state
attrs = attributeStack[last];
//handle removing attributes that were added
removedAttrs = getRemovedAttrDiff(attrs, model.toJSON());
removeAttributes(model, removedAttrs);
//restore the previous state
model.set(attrs);
//destroy the no-longer-current state
delete attributeStack[last];
}
}
});