<title>backbone.localstorage.js</title>

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<h1>backbone.localstorage.js</h1>

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<div class="content"><div class='highlight'><pre><span class="comment">/**

* Backbone localStorage Adapter

* Version 1.1.0

*

* https://github.com/jeromegn/Backbone.localStorage

*/</span>

(<span class="function"><span class="keyword">function</span> <span class="params">(root, factory)</span> {</span>

<span class="keyword">if</span> (<span class="keyword">typeof</span> define === <span class="string">"function"</span> &amp;&amp; define.amd) {</pre></div></div>

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<p>AMD. Register as an anonymous module.</p>

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<div class="content"><div class='highlight'><pre> define([<span class="string">"underscore"</span>,<span class="string">"backbone"</span>], <span class="keyword">function</span>(_, Backbone) {</pre></div></div>

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<p>Use global variables if the locals are undefined.</p>

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<div class="content"><div class='highlight'><pre> <span class="keyword">return</span> factory(_ || root._, Backbone || root.Backbone);

});

} <span class="keyword">else</span> {</pre></div></div>

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<p>RequireJS isn&#39;t being used. Assume underscore and backbone are loaded in <script> tags</p>

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<div class="content"><div class='highlight'><pre> factory(_, Backbone);

}

}(<span class="keyword">this</span>, <span class="keyword">function</span>(_, Backbone) {</pre></div></div>

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<p>A simple module to replace <code>Backbone.sync</code> with <em>localStorage</em>-based

persistence. Models are given GUIDS, and saved into a JSON object. Simple

as that.</p>

<p>Hold reference to Underscore.js and Backbone.js in the closure in order

to make things work even if they are removed from the global namespace</p>

<p>Generate four random hex digits.</p>

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<div class="content"><div class='highlight'><pre><span class="function"><span class="keyword">function</span> <span class="title">S4</span><span class="params">()</span> {</span>

<span class="keyword">return</span> (((<span class="number">1</span>+Math.random())*<span class="number">0x10000</span>)|<span class="number">0</span>).toString(<span class="number">16</span>).substring(<span class="number">1</span>);

};</pre></div></div>

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<p>Generate a pseudo-GUID by concatenating random hexadecimal.</p>

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<div class="content"><div class='highlight'><pre><span class="function"><span class="keyword">function</span> <span class="title">guid</span><span class="params">()</span> {</span>

<span class="keyword">return</span> (S4()+S4()+<span class="string">"-"</span>+S4()+<span class="string">"-"</span>+S4()+<span class="string">"-"</span>+S4()+<span class="string">"-"</span>+S4()+S4()+S4());

};</pre></div></div>

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<p>Our Store is represented by a single JS object in <em>localStorage</em>. Create it

with a meaningful name, like the name you&#39;d give a table.

window.Store is deprectated, use Backbone.LocalStorage instead</p>

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<div class="content"><div class='highlight'><pre>Backbone.LocalStorage = window.Store = <span class="keyword">function</span>(name) {

<span class="keyword">this</span>.name = name;

<span class="keyword">var</span> store = <span class="keyword">this</span>.localStorage().getItem(<span class="keyword">this</span>.name);

<span class="keyword">this</span>.records = (store &amp;&amp; store.split(<span class="string">","</span>)) || [];

};

_.extend(Backbone.LocalStorage.prototype, {</pre></div></div>

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<p>Save the current state of the <strong>Store</strong> to <em>localStorage</em>.</p>

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<div class="content"><div class='highlight'><pre> save: <span class="keyword">function</span>() {

<span class="keyword">this</span>.localStorage().setItem(<span class="keyword">this</span>.name, <span class="keyword">this</span>.records.join(<span class="string">","</span>));

},</pre></div></div>

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<p>Add a model, giving it a (hopefully)-unique GUID, if it doesn&#39;t already

have an id of it&#39;s own.</p>

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<div class="content"><div class='highlight'><pre> create: <span class="keyword">function</span>(model) {

<span class="keyword">if</span> (!model.id) {

model.id = guid();

model.set(model.idAttribute, model.id);

}

<span class="keyword">this</span>.localStorage().setItem(<span class="keyword">this</span>.name+<span class="string">"-"</span>+model.id, JSON.stringify(model));

<span class="keyword">this</span>.records.push(model.id.toString());

<span class="keyword">this</span>.save();

<span class="keyword">return</span> <span class="keyword">this</span>.find(model);

},</pre></div></div>

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<p>Update a model by replacing its copy in <code>this.data</code>.</p>

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<div class="content"><div class='highlight'><pre> update: <span class="keyword">function</span>(model) {

<span class="keyword">this</span>.localStorage().setItem(<span class="keyword">this</span>.name+<span class="string">"-"</span>+model.id, JSON.stringify(model));

<span class="keyword">if</span> (!_.include(<span class="keyword">this</span>.records, model.id.toString()))

<span class="keyword">this</span>.records.push(model.id.toString()); <span class="keyword">this</span>.save();

<span class="keyword">return</span> <span class="keyword">this</span>.find(model);

},</pre></div></div>

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<p>Retrieve a model from <code>this.data</code> by id.</p>

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<div class="content"><div class='highlight'><pre> find: <span class="keyword">function</span>(model) {

<span class="keyword">return</span> <span class="keyword">this</span>.jsonData(<span class="keyword">this</span>.localStorage().getItem(<span class="keyword">this</span>.name+<span class="string">"-"</span>+model.id));

},</pre></div></div>

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<p>Return the array of all models currently in storage.</p>

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<div class="content"><div class='highlight'><pre> findAll: <span class="keyword">function</span>() {

<span class="keyword">return</span> _(<span class="keyword">this</span>.records).chain()

.map(<span class="keyword">function</span>(id){

<span class="keyword">return</span> <span class="keyword">this</span>.jsonData(<span class="keyword">this</span>.localStorage().getItem(<span class="keyword">this</span>.name+<span class="string">"-"</span>+id));

}, <span class="keyword">this</span>)

.compact()

.value();

},</pre></div></div>

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<p>Delete a model from <code>this.data</code>, returning it.</p>

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<div class="content"><div class='highlight'><pre> destroy: <span class="keyword">function</span>(model) {

<span class="keyword">if</span> (model.isNew())

<span class="keyword">return</span> <span class="literal">false</span>

<span class="keyword">this</span>.localStorage().removeItem(<span class="keyword">this</span>.name+<span class="string">"-"</span>+model.id);

<span class="keyword">this</span>.records = _.reject(<span class="keyword">this</span>.records, <span class="keyword">function</span>(id){

<span class="keyword">return</span> id === model.id.toString();

});

<span class="keyword">this</span>.save();

<span class="keyword">return</span> model;

},

localStorage: <span class="keyword">function</span>() {

<span class="keyword">return</span> localStorage;

},</pre></div></div>

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<p>fix for &quot;illegal access&quot; error on Android when JSON.parse is passed null</p>

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<div class="content"><div class='highlight'><pre> jsonData: <span class="function"><span class="keyword">function</span> <span class="params">(data)</span> {</span>

<span class="keyword">return</span> data &amp;&amp; JSON.parse(data);

}

});</pre></div></div>

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<p>localSync delegate to the model or collection&#39;s

<em>localStorage</em> property, which should be an instance of <code>Store</code>.

window.Store.sync and Backbone.localSync is deprectated, use Backbone.LocalStorage.sync instead</p>

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<div class="content"><div class='highlight'><pre>Backbone.LocalStorage.sync = window.Store.sync = Backbone.localSync = <span class="keyword">function</span>(method, model, options) {

<span class="keyword">var</span> store = model.localStorage || model.collection.localStorage;

<span class="keyword">var</span> resp, errorMessage, syncDfd = $.Deferred &amp;&amp; $.Deferred(); <span class="comment">//If $ is having Deferred - use it.</span>

<span class="keyword">try</span> {

<span class="keyword">switch</span> (method) {

<span class="keyword">case</span> <span class="string">"read"</span>:

resp = model.id != <span class="literal">undefined</span> ? store.find(model) : store.findAll();

<span class="keyword">break</span>;

<span class="keyword">case</span> <span class="string">"create"</span>:

resp = store.create(model);

<span class="keyword">break</span>;

<span class="keyword">case</span> <span class="string">"update"</span>:

resp = store.update(model);

<span class="keyword">break</span>;

<span class="keyword">case</span> <span class="string">"delete"</span>:

resp = store.destroy(model);

<span class="keyword">break</span>;

}

} <span class="keyword">catch</span>(error) {

<span class="keyword">if</span> (error.code === DOMException.QUOTA_EXCEEDED_ERR &amp;&amp; window.localStorage.length === <span class="number">0</span>)

errorMessage = <span class="string">"Private browsing is unsupported"</span>;

<span class="keyword">else</span>

errorMessage = error.message;

}

<span class="keyword">if</span> (resp) {

model.trigger(<span class="string">"sync"</span>, model, resp, options);

<span class="keyword">if</span> (options &amp;&amp; options.success)

options.success(resp);

<span class="keyword">if</span> (syncDfd)

syncDfd.resolve(resp);

} <span class="keyword">else</span> {

errorMessage = errorMessage ? errorMessage

: <span class="string">"Record Not Found"</span>;

<span class="keyword">if</span> (options &amp;&amp; options.error)

options.error(errorMessage);

<span class="keyword">if</span> (syncDfd)

syncDfd.reject(errorMessage);

}</pre></div></div>

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<p>add compatibility with $.ajax

always execute callback for success and error</p>

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<div class="content"><div class='highlight'><pre> <span class="keyword">if</span> (options &amp;&amp; options.complete) options.complete(resp);

<span class="keyword">return</span> syncDfd &amp;&amp; syncDfd.promise();

};

Backbone.ajaxSync = Backbone.sync;

Backbone.getSyncMethod = <span class="keyword">function</span>(model) {

<span class="keyword">if</span>(model.localStorage || (model.collection &amp;&amp; model.collection.localStorage)) {

<span class="keyword">return</span> Backbone.localSync;

}

<span class="keyword">return</span> Backbone.ajaxSync;

};</pre></div></div>

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<p>Override &#39;Backbone.sync&#39; to default to localSync,

the original &#39;Backbone.sync&#39; is still available in &#39;Backbone.ajaxSync&#39;</p>

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<div class="content"><div class='highlight'><pre>Backbone.sync = <span class="keyword">function</span>(method, model, options) {

<span class="keyword">return</span> Backbone.getSyncMethod(model).apply(<span class="keyword">this</span>, [method, model, options]);

};

<span class="keyword">return</span> Backbone.LocalStorage;

}));</pre></div></div>

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