如何采摘从骨干网收集多个属性？ [英] How to pluck multiple attributes from a Backbone collection?

问题描述

我想从骨干集合采摘多个属性，但它返回未定义。

I am trying to pluck multiple attributes from a Backbone collection but it returns undefined.

集

{
    id:1,
    name:"raju",
    age:23,
    sex:male,
    hobbies:..
}
{
    id:2,
    name:"ramesh",
    age:43,
    sex:male,
    hobbies:..
}

... //many models

我试图从集合获取多个属性。

I am trying to get multiple attributes from collection.

collection.pluck(["id","name","age","sex"]);

期望的输出

[{//multiple attributes},{}]

有任何替代方式来获得多个属性？

is there any alternative way to get multiple attributes?

推荐答案

由于@elclanrs说， collection.pluck 提取一个属性，你将不得不使用 _.map 用自定义提取功能。类似

As @elclanrs said, collection.pluck extracts a single attribute, you will have to use _.map with a custom extraction function. Something like

var c = new Backbone.Collection([
    {id: 1, name: "raju", age: 23, sex: "male"},
    {id: 2, name: "ramesh", age: 43, sex: "male"}
]);

var plucked = c.map(function (model) {
    return _.pick(model.toJSON(), ["name", "age"]);
});
console.log(plucked);

和演示 http://jsfiddle.net/U7p9u/

您可以通过合并 Col​​lection.invoke 和 Model.pick

You could simplify this call by combining Collection.invoke and Model.pick

var c = new Backbone.Collection([
    {id: 1, name: "raju", age: 23, sex: "male"},
    {id: 2, name: "ramesh", age: 43, sex: "male"}
]);

plucked = c.invoke("pick", ["name", "age"]);  
console.log(plucked);

http://jsfiddle.net/U7p9u/5/

在一个类似的精神，只要您提取功能是在原型的模型定义的：

In a similar spirit, if your extraction function is defined on the prototype of your models:

var M = Backbone.Model.extend({
    mypluck: function () {
        return this.pick("name", "age");
    }
});

var C = Backbone.Collection.extend({
    model: M
});

var c = new C([
    {id: 1, name: "raju", age: 23, sex: "male"},
    {id: 2, name: "ramesh", age: 43, sex: "male"}
]);

var plucked = c.invoke("mypluck");
console.log(plucked);

http://jsfiddle.net/U7p9u/3/

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