下划线将数组转换为对象键

Question

I am trying to convert this array to an object. Using underscore, I want to convert this array :

[
{
    "id": "parentA",
    "children": [
        {
            "name": "name1"
        },
        {
            "name": "name2"
        },
        {
            "name": "name3"
        }
    ]
},
{
    "id": "parentB",
    "children": [
        {
            "name": "name4"
        },
        {
            "name": "name5"
        },
        {
            "name": "name6"
        }
    ]
}]

into an object that looks like this:

{
    "name1": "parentA",
    "name2": "parentA",
    "name3": "parentA",
    "name4": "parentB",
    "name5": "parentB",
    "name6": "parentB"
}

I'm really just looking for the cleanest/simplest way possible.

Answer 1

Here's a fairly short way to do it with two reduce :

 var data = [ { "id": "parentA", "children": [ { "name": "name1" }, { "name": "name2" }, { "name": "name3" } ] }, { "id": "parentB", "children": [ { "name": "name4" }, { "name": "name5" }, { "name": "name6" } ] }]; var out = _.reduce(data, function(result, parent) { _.reduce(parent.children, function(r, child) { r[child.name] = parent.id; return r; }, result); return result; }, {}); document.write(JSON.stringify(out)); 

 <script src="http://underscorejs.org/underscore-min.js"></script> 

Answer 2

 var a = [{ "id": "parentA", "children": [{ "name": "name1" }, { "name": "name2" }, { "name": "name3" }] }, { "id": "parentB", "children": [{ "name": "name4" }, { "name": "name5" }, { "name": "name6" }] }]; var new_obj = {}; var len = a.length; for (j = 0; j < len; j++) { var c = $.extend({}, a[j]); var children_length = (c.children).length; for (i = 0; i < children_length; i++) { var temp = ((a[j].children)[i]).name; new_obj[temp] = c.id; } } document.write(JSON.stringify(new_obj)); 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> 

Answer 3

You'll only need to use underscore if you're supporting browsers without native reduce and forEach array methods, but you can do it like this.

var result = _.reduce(array, function(memo, entry) {
    _.each(entry.children, function(child) {
        memo[child.name] = entry.id;
    });
    return memo;
}, {});

Answer 4

function expand(list){
  return _.reduce(list,function(a,b) {
      _.each(b.children, function(c) {
      a[c.name] = b.id;
    });
    return a;
  },{});
}

Check the output for your sample here