Javascript Array conversion

Question

I was wondering how I could turn this:

var data = [  
     {id:1,option1:'short',option2:'red',option3:'gold'},  
     {id:2,option1:'short',option2:'red',option3:'silver'},   
     {id:3,option1:'short',option2:'blue',option3:'gold'},  
     {id:4,option1:'short',option2:'blue',option3:'silver'},  
     {id:5,option1:'long',option2:'red',option3:'gold'},  
     {id:6,option1:'long',option2:'red',option3:'silver'},   
     {id:7,option1:'long',option2:'blue',option3:'gold'},  
     {id:8,option1:'long',option2:'blue',option3:'silver'}]

Into something formatted like this using Jquery.

var new_data = {
            short:{
              red:{gold:1,silver:2},
              blue:{gold:3,silver:4}
            },
            long:{
              red:{gold:5,silver:6},
              blue:{gold:7,silver:8}
               }
       }

You can, you just have to sift through the data and create the object yourself. I'll make you a fiddle. — RestingRobot, Apr 25 '13 at 17:10
Question - are your input and output stuff objects that are already in memory, or just text? If they're objects, you can walk through the object using loops to reformat as you see fit. — Sébastien Renauld, Apr 25 '13 at 17:10
@Sebastien Renauld If it is a string, he can use `parse()` to make it into an object — RestingRobot, Apr 25 '13 at 17:13
Doesn't look like it is a string. His example uses an array literal. — rlemon, Apr 25 '13 at 17:14

score 4 · Accepted Answer · answered Apr 25 '13 at 17:16

4

That is easier than you might think. Try this:

function helper(obj,tree,value) {
    for( var i=0, l=tree.length; i<l-1; i++) {
        obj[tree[i]] = obj[tree[i]] || {};
        obj = obj[tree[i]];
    }
    obj[tree[i]] = value;
}
var new_data = {}, l = data.length, i;
for( i=0; i<l; i++) {
    helper(new_data,[data[i].option1,data[i].option2,data[i].option3],data[i].id);
}

answered Apr 25 '13 at 17:16

Niet the Dark Absol

320,036
81
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Nicely done, faster and better than my implementation. – RestingRobot Apr 25 '13 at 17:17

Bergi · Answer 2 · 2013-04-25T17:21:40.963

1

This plain JS will do it:

var data = […];
var new_data = {};
for (var i=0; i<data.length; i++) {
    var o = new_data;
    for (var j=1; j<3; j++) {
        var prop = data[i]["option"+j];
        o = o[prop] || (o[prop] = {});
    }
    o[data[i]["option"+j]] = data[i].id;
}

But it looks easier to use that nested schema in the first place?

edited Apr 25 '13 at 17:21

answered Apr 25 '13 at 17:13

Bergi

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1,375

You solution doesn't provide the correct result, it only returns the silver counts. – RestingRobot Apr 25 '13 at 17:16
@Jlange: If you're executing this in the console, you'll need to add an explicit `return JSON.stringify(new_data, null, 4)` of course (otherwise it will only print `8`, i.e. the last id) – Bergi Apr 25 '13 at 17:18
No, I ran it in my fiddle, it doesn't return the proper data structure – RestingRobot Apr 25 '13 at 17:20
@Jlange: [Better?](http://jsfiddle.net/9wTQf/) – Bergi Apr 25 '13 at 17:23

zap · Answer 3 · 2013-04-25T17:44:03.047

You can use .reduce() like this:

var new_data = data.reduce(function(res, obj) {
    if (!res[obj.option1])
        res[obj.option1] = {};
    if (!res[obj.option1][obj.option2])
        res[obj.option1][obj.option2] = {};

    res[obj.option1][obj.option2][obj.option3] = obj.id;
    return res;
}, {});

or like this:

var new_data = data.reduce(function(res, obj) {
    var o = res;
    for (var i = 1; i < 3; i++)
        o = (o[obj["option" + i]] = o[obj["option" + i]] || {});

    o[obj.option3] = obj.id;
    return res;
}, {});

Javascript Array conversion

3 Answers3