使用JavaScript遍历JSON-查找具有某些父值的子级

Question

JSON:

{resources:
    [
    {type:sound, content:0},
    {type:movie, content:1},
    {type:image, content:2},
    ...
]}

How do i most effeciently get the content of objects with type=image? can i avoid having to loop through the objects?

Coming from a background working with xml i am used to working with queries inside the getter.

The above sample in xml would let me get the content of the image object by simply writing resources.object(type == "image").content

<resources>
    <object type="sound">
        <content>0</content>
    </object>
    <object type="movie">
        <content>1</content>
    </object>
    <object type="image">
        <content>2</content>
    </object>
    ...
</resources>

Answer 1

You can use lodash for this.

In your case the solution would look like this -

_.filter(resources, { 'type': 'image' });

Answer 2

In vanilla javascript you can use filter to filter them and map to get an array of the contents:

let json = {resources:
    [
    {type:"sound", content:0},
    {type:"movie", content:1},
    {type:"image", content:2}
]}; 

json.resources.filter( r => r.type === "image" ).map( r => r.content)