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POBackbone tutorial: model.destroy + remove and unrender functions
 

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  1. POBackbone tutorial: model.destroy + remove and unrender functions
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    <p>I am trying to understand this sample backbone codes from this <a href="http://arturadib.com/hello-backbonejs/docs/5.html" rel="nofollow">tutorial</a>, but I can't get my head around why we need this is <code>dummy function</code> - any ideas what it is for?</p> <pre><code> Backbone.sync = function(method, model, success, error){ success(); } </code></pre> <p>Then, <code>remove</code> and <code>unrender</code> functions seem to be the same - why do we need both of them?</p> <p>And what is this line for,</p> <pre><code>this.model.bind('remove', this.unrender); </code></pre> <p>while we have bound the <code>remove</code> function and the click event to the dom?</p> <p>also, we already have bound all functions (including <code>unrender</code>) in this line,</p> <pre><code>_.bindAll(this, 'render', 'unrender', 'swap', 'remove'); </code></pre> <p>so why do we need this line below?</p> <pre><code>this.model.bind('remove', this.unrender); </code></pre> <p>You can read the entire code from that tutorial above, here is some of it,</p> <pre><code>// `Backbone.sync`: Overrides persistence storage with dummy function. This enables use of `Model.destroy()` without raising an error. Backbone.sync = function(method, model, success, error){ success(); } var Item = Backbone.Model.extend({ defaults: { part1: 'hello', part2: 'world' } }); var List = Backbone.Collection.extend({ model: Item }); var ItemView = Backbone.View.extend({ tagName: 'li', // name of tag to be created // `ItemView`s now respond to two clickable actions for each `Item`: swap and delete. events: { 'click span.swap': 'swap', 'click span.delete': 'remove' }, // `initialize()` now binds model change/removal to the corresponding handlers below. initialize: function(){ _.bindAll(this, 'render', 'unrender', 'swap', 'remove'); // every function that uses 'this' as the current object should be in here this.model.bind('change', this.render); this.model.bind('remove', this.unrender); }, // `render()` now includes two extra `span`s corresponding to the actions swap and delete. render: function(){ $(this.el).html('&lt;span style="color:black;"&gt;'+this.model.get('part1')+' '+this.model.get('part2')+'&lt;/span&gt; &amp;nbsp; &amp;nbsp; &lt;span class="swap" style="font-family:sans-serif; color:blue; cursor:pointer;"&gt;[swap]&lt;/span&gt; &lt;span class="delete" style="cursor:pointer; color:red; font-family:sans-serif;"&gt;[delete]&lt;/span&gt;'); return this; // for chainable calls, like .render().el }, // `unrender()`: Makes Model remove itself from the DOM. unrender: function(){ $(this.el).remove(); }, // `swap()` will interchange an `Item`'s attributes. When the `.set()` model function is called, the event `change` will be triggered. swap: function(){ var swapped = { part1: this.model.get('part2'), part2: this.model.get('part1') }; this.model.set(swapped); }, // `remove()`: We use the method `destroy()` to remove a model from its collection. Normally this would also delete the record from its persistent storage, but we have overridden that (see above). remove: function(){ this.model.destroy(); } }); </code></pre>
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