按枚举序列的特定顺序对 backbone collection 进行排序

Question

我的 backbone collection 如下：

var model1 = new Backbone.Model({mode: 'EX'});
var model2 = new Backbone.Model({mode: 'AB'});
var model3 = new Backbone.Model({mode: 'DF'});
var model4 = new Backbone.Model({mode: 'AB'});
var model5 = new Backbone.Model({mode: 'DF'});
var model6 = new Backbone.Model({mode: 'AB'});

var myCollection =  new backbone.Collection([model1,model2,model3,model4,model5, model6]);

现在我希望这个 collection 按一些业务顺序排序，假设所有模型首先具有 'DF' 模式，然后所有模型具有 'AB' 模式，最后是模型'EX'.

需要输出

/*my Collection.models should contains array of models in following sequence
after sorting */
[model3, model5, model2, model4, model6, model1]

我有另一个 java 脚本 object 我将根据它来决定这个模式序列。例如

var enum = {
  1: 'DF',
  2: 'AB',
  3: 'EX'
}

所以这里字符串排序是没有用的。有人可以建议我如何在 backbone collection 上编写比较器来完成此排序

Answer 1

您需要使用自定义 comparator 扩展默认值 Backbone.Collection：

var priority= ['DF', 'AB', 'EX'];

var Collection = Backbone.Collection.extend({
  comparator: function(a, b) {
    return priority.indexOf(a.get('mode')) > priority.indexOf(b.get('mode'));
  }
});
var myCollection = new Collection([{
  mode: 'EX'
}, {
  mode: 'AB'
}, {
  mode: 'DF'
}, {
  mode: 'AB'
}, {
  mode: 'DF'
}, {
  mode: 'AB'
}]);
console.log(myCollection.pluck('mode'));

<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/backbone.js/1.3.3/backbone-min.js"></script>

或使用对象图：

var priority = {
  1: 'DF',
  2: 'AB',
  3: 'EX'
}

var Collection = Backbone.Collection.extend({
  comparator: function(a, b) {
    var i = _.findKey(priority, function(val) {
      return val === a.get('mode')
    });
    var j = _.findKey(priority, function(val) {
      return val === b.get('mode')
    });
    return i > j;
  }
});
var myCollection = new Collection([{
  mode: 'EX'
}, {
  mode: 'AB'
}, {
  mode: 'DF'
}, {
  mode: 'AB'
}, {
  mode: 'DF'
}, {
  mode: 'AB'
}]);
console.log(myCollection.pluck('mode'));

<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/backbone.js/1.3.3/backbone-min.js"></script>

Answer 2

我会翻转枚举器，这样您就可以轻松地对其进行索引。

var enumerator = {
  DF: 1,
  AB: 2,
  EX: 3
};

var YourModel = Backbone.Model.extend({
  defaults: {
    mode: ''
  }
});

var YourCollection = Backbone.Collection.extend({
  model: YourModel,
  comparator: function(m) {
    return enumerator[m.get('mode')];
  }
});

var yourCollection = new YourCollection([
  { mode: 'EX' },
  { mode: 'AB' },
  { mode: 'DF' },
  { mode: 'AB' }
]);

console.log(yourCollection.pluck('mode')); // ["DF", "AB", "AB", "EX"]

按枚举序列的特定顺序对 backbone collection 进行排序

Sort backbone collection in specific order of enum sequence

backbone.js

backbone.js-collections