Mr. Crowley Mr. Crowley - 17 days ago 5
Javascript Question

Backbone.js multiple tables data manipulation

I have 3 separate tables in my page and they all get filled on View Initialize and fetch their data from my backend REST Api. After fetching data i bind the reset to method called

paint
and inside that loop through the collection and construct the table.

paintSelected: function (collection, options) {
collection.each(function (ch) {
var view = new ChannelViewDetailed({model: ch});
view.setOwner(collection);
this.$el.find('#selected tr:eq(' + collection.indexOf(ch) + ')').after(view.render().el);
}, this);
},


this constructs the whole table on my defined underscore template. all is fine at this point and i can handle remove and add data between the multiple collections on this page.

When i want to perform an
exclude all
or
include all
operation on this tables things get messed up, the view owners get lost due to loops that i have to make, duplicates show up in the list and ordering gets lost.

ChannelViewDetailed = Backbone.View.extend({
tagName: 'tr',
template: _.template($('#tpl-channel-row-detailed').html()),

events: {
'click td.del': 'deleteSelected'
},

setOwner: function (collection) {
this.owner = collection;
},

render: function () {
this.$el.html(this.template(this.model.toJSON()));
return this;
},

deleteSelected: function (e) {
e.preventDefault();
this.owner.remove(this.model);
this.remove();
}
});


please note that all that was mentioned above works fine when performing per item actions, but doesn't function as expected when i wan't to perform batch (include all / exclude all) operations.

this is a sample of exclude all method i've trying to accomplish.

excludeAllChannels: function (e) {
e.preventDefault();
var self = this;

if (!$.isEmptyObject(self.selected)) {
_.each(this.selected.models, function (item, index, items) {
self.selected.remove(item);
});
$('#in-channels tr').has('td').remove();
unsavedState = true;
}
}

Answer

Modification of an array you are currently looping through can cause unexpected results.

https://jsfiddle.net/c0xpzq6v/

var a = new Backbone.Collection(data);
_.each(a.models, function(item) { a.remove(item); });

Can be replaced by any of the following

_.each(_.clone(a.models), function(item) { a.remove(item); });
a.remove(a.models);
a.reset();
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