CODEWITHSUNDEEP
javascriptdestructuringecmascript-2016ecmascript-next
CodingIntrigue
CodingIntrigue

Reputation: 78525

Destructure array to object property keys

I have an array of values like:

const arr = [1,2,3];

Is there any way I can use destructuring to create the following output? If not, what is the easiest way I can do this in ES6 (or later)?

const obj = {
    one: 1,
    two: 2,
    three: 3
};

I tried this, but I guess it doesn't work as this is the syntax for computed keys:

const arr = [1,2,3];
const obj = {
  [one, two, three] = arr
};

Upvotes: 42

Views: 24383

Answers (10)

Aravinth Loganathan
Aravinth Loganathan

Reputation: 1

  

const arr = [1,2,3]
const [one,two,three] = arr
const newObj = {one,two,three}
    
console.log(newObj)

Upvotes: 0

Fabiano Taioli
Fabiano Taioli

Reputation: 5540

Arrow flavor:

const obj = (([one, two, three]) => ({one, two, three}))(arr)

Upvotes: 2

Islam Sayed
Islam Sayed

Reputation: 56

One of the easiest and less code way is to destructure the array. Then use such constants to update the object.

const arr = [1, 2, 3];
const [one, two, three] = arr;
const obj = {one, two, three};

console.log(obj);

Notice how I assigned values to the object by such writing the names of the constants one, two, and three. You can do so when the name of the key is the same of the property.

//Instead of writing it like this
const obj = {one: one, two: two, three: three};

Upvotes: 0

user6445533
user6445533

Reputation:

You can assign destructured values not only to variables but also to existing objects:

const arr = [1,2,3], o = {};    
({0:o.one, 1:o.two, 2:o.three} = arr);

This works without any additional variables and is less repetitive. However, it also requires two steps, if you are very particular about it.

Upvotes: 47

T.J. Crowder
T.J. Crowder

Reputation: 1074138

I don't believe there's any structuring/destructuring solution to doing that in a single step, no. I wanted something similar in this question. The old := strawman proposal doesn't seem to have legs in the new proposal list, so I don't think there's much activity around this right now.

IMHO, this answer is the best one here (much better than this one). Two steps, but concise and simple.

But if it's two steps, you could also use a simple object initializer:

const arr = [1,2,3];
const obj = {
  one: arr[0],
  two: arr[1],
  three: arr[2]
};
console.log(obj);

Another option is to do it with several temporary arrays but technically only one statement (I am not advocating this, just noting it):

const arr = [1,2,3];
const obj = Object.fromEntries(
    ["one", "two", "three"].map((name, index) =>
        [name, arr[index]]
    )
);
console.log(obj);

Upvotes: 14

Amit
Amit

Reputation: 1

let distructingNames = ['alu', 'bob', 'alice', 'truce', 'truce', 'truce', 'truce', 'bob'];
let obj={};
distructingNames.forEach((ele,i)=>{
    obj[i]=ele;
})
console.log('obj', obj)

Upvotes: 0

Technotronic
Technotronic

Reputation: 8943

You can achieve it pretty easily using lodash's _.zipObject

const obj = _.zipObject(['one','two','three'], [1, 2, 3]);
console.log(obj); // { one: 1, two: 2, three: 3 }

Upvotes: 0

Mario
Mario

Reputation: 4988

Using destructuring assignment it is possible to assign to an object from an array

Please try this example:

const numbers = {};

[numbers.one, numbers.two, numbers.three] = [1, 2, 3]

console.log(numbers)

The credit to the boys of http://javascript.info/ where I found a similar example. This example is located at http://javascript.info/destructuring-assignment in the Assign to anything at the left-side section

Upvotes: 6

adambullmer
adambullmer

Reputation: 1012

With destructuring, you can either create new variables or assign to existing variables/properties. You can't declare and reassign in the same statement, however.

const arr = [1, 2, 3],
    obj = {};

[obj.one, obj.two, obj.three] = arr;
console.log(obj);
// { one: 1, two: 2, three: 3 }

Upvotes: 22

corse32
corse32

Reputation: 166

This answers a slightly different requirement, but I came here looking for an answer to that need and perhaps this will help others in a similar situation.

Given an array of strings : a = ['one', 'two', 'three'] What is a nice un-nested non-loop way of getting this resulting dictionary: b = { one : 'one', two: 'two', three: 'three' } ?

const b = a.map(a=>({ [a]: a })).reduce((p, n)=>({ ...p, ...n }),{})

Upvotes: 3

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