What's the best way to convert an array, to an object with those array values as keys, empty strings serve as the values of the new object.
['a','b','c']
to:
{
a: '',
b: '',
c: ''
}
5 Answers
Try with Array.reduce():
const arr = ['a','b','c'];
const res = arr.reduce((acc,curr)=> (acc[curr]='',acc),{});
console.log(res)
5 Comments
Shivam Sahil
whatt does returning
(a[b] = '',a) mean? what does the second argument do?
prasanth
@ShivamSahil check now, I have edited the answer. Each time of the loop
current value inserted into accumulator acc[curr] = '' like this. ,acc is returning the accumulator once loop end. And ,{} is defined the accumulator is a object
cbdeveloper
Could somebody add a Typescript version of this?
prasanth
@cbdeveloper typescript version mycompiler.io/view/AlipcFS
Cezar D.
@ShivamSahil a good explanation of how the comma operator works: developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…
You can use Array.prototype.reduce()and Computed property names
let arr = ['a','b','c'];
let obj = arr.reduce((ac,a) => ({...ac,[a]:''}),{});
console.log(obj);
3 Comments
Tofandel
Why do simple when you can do complicated...
Jean Paul
From an eslint point of view this syntax is less ambiguous than the most voted one, +1.
Dmitry Vasilev
Your solution is slower then "arr.reduce((ac,a)=>(ac[a]='',ac),{})" because off object is recreated at every iteration
const target = {}; ['a','b','c'].forEach(key => target[key] = "");
6 Comments
Serge K.
Why do you use
map to iterate over an array ? You could have chosen forEach
HMR
Usually Array.prototype.map is used to create a new array and the function passed to map is a pure function.
Tofandel
I don't understand why everybody was trying to complicate everything with reduce when there was such an obvious and simple answer
user0103
@Tofandel because this is perfect and handy usage of
reduce... forEach requires variable declaration, reduce is true one-liner and this is kind of task it was designed for. It's definitely not 'complicated'.Tofandel
"True one-liners" are just making code more obscure and harder to understand. Better to add one line and have a code you can understand right away
|
You can use the Object.assign property to combine objects created with a map function. Please take into account that, if the values of array elements are not unique, the latter ones will overwrite previous ones.
const array = Object.assign({},...["a","b","c"].map(key => ({[key]: ""})));
console.log(array);
answered Feb 20, 2019 at 15:08
Krzysztof Krzeszewski
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Comments
You can use the array reduce function and pass an empty object in the accumulator. In this accumulator, add a key which is denoted by curr.
let k = ['a', 'b', 'c']
let obj = k.reduce(function(acc, curr) {
acc[curr] = '';
return acc;
}, {});
console.log(obj)Another option is to use for..of loop
let k = ['a', 'b', 'c'];
const obj = {};
for (let keys of k) {
obj[keys] = '';
}
console.log(obj)
1 Comment
CarlosCarucce
I think this one have the most readable 'reduce' approach
Object.fromEntries(['a', 'b', 'c'].map(k => [k, '']));