Converting an Array into object in Javascript

Question

I want to know the best way to convert an array in Js to object.

This is the sample of what i want to do. Input => ['abc', 'def']; Output => { abc: true, def: true }

I have done it using the code below. But just wanted to know if

**function toObject(strings) {
    var rv = {}
    strings.forEach(string => {
        rv[string] = true
    })
  return rv
}**

This function serves the purpose. But any experts out there with a best and efficient way possible.

strings.reduce( (a,c) => (a[c]=true, a), {})

gurvinder372
– gurvinder372

2018-04-12 12:41:05 +00:00
Commented Apr 12, 2018 at 12:41 — gurvinder372
– gurvinder372, Commented Apr 12, 2018 at 12:41
Your function itself is good enough.

Aniket Sinha
– Aniket Sinha

2018-04-12 12:45:32 +00:00
Commented Apr 12, 2018 at 12:45 — Aniket Sinha
– Aniket Sinha, Commented Apr 12, 2018 at 12:45

gurvinder372 · Accepted Answer · 2018-04-12 12:42:48Z

2

Not sure what you mean by best and efficient way possible, since yours is alright according to me, this is a less versbose version

var output = strings.reduce( (a,c) => (a[c]=true, a), {})

Demo

var strings = ['abc', 'def'];
var output = strings.reduce( (a,c) => (a[c]=true, a), {});
console.log(output);

answered Apr 12, 2018 at 12:42

gurvinder372

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3 Comments

Prawal Sharma Over a year ago

"a[c]=true" - I understood this part. But can you please explain me the second part - ",a". All in all i want to know what this second parameter is doing after comma (a[c]=true, a). Is this assigning value in a.

gurvinder372 Over a year ago

That is the value returned by expression in () braces as output of every iteration. Please read up about reduce

Prawal Sharma Over a year ago

Thanks for the reply. Now i understood it completely.

Nina Scholz · Accepted Answer · 2018-04-12 12:42:33Z

1

You could map single objects and assign it to the same object.

var array = ['abc', 'def'],
    object = Object.assign(...array.map(key => ({ [key]: true })));
    
console.log(object);

answered Apr 12, 2018 at 12:42

Nina Scholz

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2 Comments

gurvinder372 Over a year ago

Nice, didn't thought of using Object.assign myself +1

Prawal Sharma Over a year ago

Thanks for the quick reply. I also didn't gave a thought for this.

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