combining multiple arrays into an object with first array items as the key

Question

I have these following arrays

var category = ['Guitar', 'Bass', 'Amps'];


var platform_a = ['platform-a1','platform-a2','platform-a3'];
var platform_b = ['platform-b1','platform-b2','platform-b3'];
var platform_c = ['platform-c1','platform-c2','platform-c3'];

And I want to convert them into a json which should look like this

{
    "Guitar":["platform-a1","platform-a2","platform-a3"],
    "Bass":["platform-b1","platform-b2","platform-b3"],
    "Amp":["platform-c1","platform-c2","platform-c3"]
}

How would I do this? I would have to do this in pure javascript

do you know the number of categories and number of platforms? would you get the platforms as an array or as variables like so? — Gal Schlezinger
– Gal Schlezinger, Commented Sep 30, 2014 at 20:55
I do know the number of categories..so each category might have different number of platforms..so lets say Gitar mght have 15 bass has 10 and Amp has 4..but no..i cant say they would be a static number — soum
– soum, Commented Sep 30, 2014 at 21:00
my question is.. If this is hard-coded inside your codebase.. because if it ain't you'll need to go and reduce this guys ;P — Gal Schlezinger
– Gal Schlezinger, Commented Sep 30, 2014 at 21:03

Giannis Grivas · Accepted Answer · 2014-09-30 22:41:31Z

2

Let's present three different approaches to your case:

First one

If you want just to create the json object with your data try:

http://jsfiddle.net/csdtesting/tap2xom9/

var platform_a = ['platform-a1', 'platform-a2', 'platform-a3'];
var platform_b = ['platform-b1', 'platform-b2', 'platform-b3'];
var platform_c = ['platform-c1', 'platform-c2', 'platform-c3'];
var category = ['Guitar', 'Bass', 'Amps'];

var obj = {
  Guitar: platform_a,
  Bass: platform_b,
  Amps: platform_c
};
document.write(JSON.stringify(obj));

Second

If you want to create it dynamically do something like that:

http://jsfiddle.net/csdtesting/tap2xom9/

var category = ['Guitar', 'Bass', 'Amps'];
var platform_a = ['platform-a1', 'platform-a2', 'platform-a3'];
var platform_b = ['platform-b1', 'platform-b2', 'platform-b3'];
var platform_c = ['platform-c1', 'platform-c2', 'platform-c3'];

var FinalObject = {};

FinalObject[category[0]] = platform_a;
FinalObject[category[1]] = platform_b;
FinalObject[category[2]] = platform_c;

document.write(JSON.stringify(FinalObject));

Finally

If you want to be more dynamic then try this :

http://jsfiddle.net/csdtesting/kqwz72os/

var FinalObject = {};

var category = ['Guitar', 'Bass', 'Amps'];
var platforms = {
  platform_a: ['platform-a1', 'platform-a2', 'platform-a3'],
  platform_b: ['platform-b1', 'platform-b2', 'platform-b3'],
  platform_c: ['platform-c1', 'platform-c2', 'platform-c3']
};
for (var i = 0; i < category.length; i++) {
  FinalObject[category[i]] = platforms[Object.keys(platforms)[i]];
}

document.write(JSON.stringify(FinalObject));

Hope this helps!

answered Sep 30, 2014 at 22:41

Giannis Grivas

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1 Comment

soum Over a year ago

This totally works for couple fo reasons...1: I dont have to hard code the values like Tj is doing..2: its sclable becuse the category array can grow and so the number of platforms...so basically it is very dynamic..thanks for the direction..really appriciate it

T.J. Crowder · Accepted Answer · 2014-09-30 20:51:15Z

1

There's no reasonable shortcut here. You just have to do it manually:

var jsonString = JSON.stringify({
    "Guitar": platform_a,
    "Base": platform_b,
    "Amp": platform_c
});

answered Sep 30, 2014 at 20:51

T.J. Crowder

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