Use variable outside the object to be the object variable

Question

I have this code

for (var i = 0; i < lootbox.length; i++) {
  const { type } = lootbox[i]
  const query = type + "_lootbox.hunt";

  await lb.findOneAndUpdate(
    { userID: message.author.id },
    { $inc: { query: 1 } }
  );
}

the code reads the query as its own variable instead of the type + "_lootbox.hunt", is there a way to use that query inside the $inc? because I want to automate it using the loop

AKA. dynamic object key

How about `query: query` instead of hard-coding `1`? Is that actually what you're asking? — Pointy, Sep 26 '21 at 01:06
err I want to increment it by 1, with the `type + "_lootbox.hunt"` — Coding newbies, Sep 26 '21 at 01:08
Well your code as posted makes no attempt to do anything of that sort. — Pointy, Sep 26 '21 at 01:18
Your title isn't very clear, what *variable outside the object*? Which *object*? To be *the object variable*, which object variable? See where im going with this — Elitezen, Sep 26 '21 at 01:21
sorry my english isnt good, I mean to access that `query` inside the `findOneAndUpdate` — Coding newbies, Sep 26 '21 at 01:26
https://stackoverflow.com/questions/6500573/dynamic-keys-for-object-literals-in-javascript I think this answers my questions thank you — Coding newbies, Sep 26 '21 at 01:50

score 0 · Answer 1 · answered Sep 26 '21 at 01:51

The problem here is that you are trying to create an object on the fly, but you can not set a key like that dynamically.

To achieve that you need to prepare this object prior to use.

And, in such a case your code would be something like this,

for (var i = 0; i < lootbox.length; i++) {
  const { type } = lootbox[i]
  const query = type + "_lootbox.hunt";
  const tempObject = {}; // Creating an empty Object
  tempObject[query] = 1; // Dynamic key usage
  await lb.findOneAndUpdate(
    { userID: message.author.id },
    { $inc: tempObject } // Using the tempObject
  );
}

score 0 · Answer 2 · answered Sep 26 '21 at 02:46

As I understand what you want is this: in each iteration query becomes type + "_lootbox.hunt", for example page1_lootbox.hunt. And what you want to get is { $inc: { "page1_lootbox.hunt": 1 }}. If so, a simple solution will be

{ $inc: { [query]: 1 } }    // { $inc: { "page1_lootbox.hunt": 1 } }

Let me know if you want something different.

Use variable outside the object to be the object variable

2 Answers2