Javascript array reduce convert array to object with integer keys

Question

I am trying to convert an array of objects to objects with reduce method. The problem is I want to have object keys in numeric.

let crops = [{
  id: 1,
  name: "wheat"
}, {
  id: 2,
  name: "rice"
}];

let cropsObj = crops.reduce((accumulator, currentValue) => {
  accumulator[currentValue.id] = currentValue.name
  return accumulator;
}, {});

console.log(cropsObj);

This works fine except the keys I am getting are strings. For example:

{"1":"wheat","2":"rice"}

What I want is {1:"wheat",2:"rice"}. How can I convert the keys to integers?

Keys can only be strings (or Symbols) in javascript objects. If you need some other key an es6 Map might be an option. — Mark
– Mark, Commented May 24, 2019 at 20:53
An array has integer "keys", but there are performance implications to sparse arrays. You might want to look into Map... — Heretic Monkey
– Heretic Monkey, Commented May 24, 2019 at 20:54
@HereticMonkey If neglecting performance for a moment, How will I have integer keys ? — Raheel
– Raheel, Commented May 24, 2019 at 20:57
{"1":"wheat","2":"rice"} and {1:"wheat",2:"rice"} are same thing, JS internally converts them to string — Rikin
– Rikin, Commented May 24, 2019 at 20:57

junvar · Accepted Answer · 2019-05-25 17:23:41Z

2

To illustrate @MarkMeyer's comment:

Keys can only be strings (or Symbols) in javascript objects.

console.log({3: 4, '3': 5});

edited May 25, 2019 at 17:23

answered May 24, 2019 at 20:56

junvar

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Comments

Leftium · Accepted Answer · 2019-05-24 21:06:20Z

1

For your purposes (using material-table), your current objects will work fine. {1:"wheat"} is effectively the same as {"1":"wheat"}.

Unquoted property names / object keys in JavaScript gives a very detailed explanation of why. In short, numeric property names can be used, but they will be coerced into strings.

answered May 24, 2019 at 21:06

Leftium

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Ajit Kumar · Accepted Answer · 2019-05-24 21:11:19Z

1

let obj = {
  key: 4,
  123: 'one two three',
  1: 'one'
};

console.log(obj.key);
//console.log(obj.1); error
console.log(obj["1"]);
console.log(obj["123"]);

console.log(obj[1]);
console.log(obj[123]);

It is not possible because key in any JavaScript object is a JavaScript identifier or a string.

edited May 24, 2019 at 21:11

answered May 24, 2019 at 20:55

Ajit Kumar

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