如何使用AngularJS过滤对象属性

Question

I have a array of categories object

categoriesTree : [
    {name: 'cat1', id:1, selected : true},
    {name: 'cat2', id:2, selected : false},
    {name: 'cat3', id:3, selected : true},
    {name: 'cat4', id:4, selected : false},
    {name: 'cat6', id:6, selected : true},
]

To get the selected categories I did:

selectedCategories = filterFilter($scope.categoriesTree, {selected:true})

this will give me:

categoriesTree : [
    {name: 'cat1', id:1, selected : true},
    {name: 'cat3', id:3, selected : true},
    {name: 'cat6', id:6, selected : true},
]

But to reduce the POST data to send, I just want the id attribue so I want an array like this:

['1', '3', '6']

Is that possible to do with AngularJS filters ?

Answer 1

res = categoriesTree.map(function(el) { return el.id; });

Short and simple, with the good ole js.

To answer your question: no, with filters you can't, but it is possible with forEach

Answer 2

You can create your own custom angularjs filter that not only "filters" but also "projects" your set into a different set. I think you can definitely project each category object into just its ID.

See here for an example of how to create a custom filter in angularjs.

Answer 3

you can use underscorejs's _.pluck method.

selectedCategories = _.pluck(_.filter(categoriesTree, function(category) {
    return category.selected;
}), 'id');

which returns an array of the values of all the id 's where the corresponding selected value is true .