How to dynamically create objects with variables

Question

I have some variables in a loop which are different each iteration.

With those variables I want to fill a new object with some sub objects like so:

newProduct[key][prop][val] = "value";

What I want is an object like

car{ //key
   color: { //prop
       door: "value" //val + value
   }
}

But my problem is that [val] is not an object from [prop] and that is what Node.JS is trying to do.

I have tried it some other brackets like [prop[val]] and [prop + "." + val], but that doesn't seems to work. How can I get this to work?

I think you need to show us what do you have and what do you want? — hurricane
– hurricane, Commented Nov 3, 2017 at 11:37

Nina Scholz · Accepted Answer · 2017-11-03 11:37:24Z

2

You could check every property and use a default object. Later assign the value

function setValue(object, path, value) {
    var last = path.pop();
    path.reduce((o, k) => o[k] = o[k] || {}, object)[last] = value;
}

var newProduct = {};

setValue(newProduct, ['car', 'color', 'door'], 42);

console.log(newProduct);

.as-console-wrapper { max-height: 100% !important; top: 0; }

answered Nov 3, 2017 at 11:37

Nina Scholz

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Comments

segu · Accepted Answer · 2017-11-03 11:55:04Z

1

Try with Object assign like that:

// It should be every iteration values
var key = 'car';
var prop = 'color';
var val = 'door';
var value = 'value';

var newProduct = Object.assign({ [ key ] :{ [ prop ] : { [ val ] : value }} });
console.log(newProduct);

edited Nov 3, 2017 at 11:55

answered Nov 3, 2017 at 11:44

segu

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Comments

ADyson · Accepted Answer · 2017-11-03 11:38:31Z

0

You need to create each object at each layer before you can use it. Here's a very simple example. You could refine it to make it more re-usable, obviously:

var newProduct = {};
if (!newProduct["car"]) newProduct["car"] = {};
if (!newProduct["car"]["color"]) newProduct["car"]["color"] = {};
newProduct["car"]["color"]["door"] = "value";
console.log(newProduct);

answered Nov 3, 2017 at 11:38

ADyson

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