CODEWITHSUNDEEP
javascriptarrays
ololo
ololo

Reputation: 2036

Find Object in an array that has the highest number of keys

I have a sample Array of objects like this

let items = [
    {
        a: '',
        b: 2,
        c: 3
    },
    {
        a: '',
        b: '',
        c: 5,
        d: 10
    },
    {
        a: '',
        b: '',
        c: 6,
    }
]

I want to find the first object that has the highest number of keys.

Clearly from the above, the second object has the highest number of keys.

How can I achieve this?

Thank you.

Upvotes: 0

Views: 834

Answers (2)

PeterKA
PeterKA

Reputation: 24638

Start by .sort()ing in descending order by number of keys. Then return the first element.

let items = [{
        a: '',
        b: 2,
        c: 3
    },
    {
        a: '',
        b: '',
        c: 5,
        d: 10
    },
    {
        a: '',
        b: '',
        c: 6,
    }
];

const mostkeys = items.sort(
    (a,b) => Object.keys(b).length - Object.keys(a).length
)[0];

console.log( mostkeys );

If, however, you have more than one having the most keys and you would like to return all, your approach would be slightly different at the last step:

let items = [{
        a: '',
        b: 2,
        c: 3
    },
    {
        a: '',
        b: '',
        c: 5,
        d: 10
    },
    {
        a: '',
        b: '',
        c: 6,
    },
    {
        c: '',
        d: '',
        e: 6,
        f: 3
    }
];

const mostkeys = items.sort(
    (a,b) => Object.keys(b).length - Object.keys(a).length
)
.reduce((m, cur, i, a) => 
    i === 0 ? [...m,cur] : Object.keys(cur).length < Object.keys(m[0]).length ? m : [...m,cur], []
);

console.log( mostkeys );

Upvotes: 1

Connor Mooneyhan
Connor Mooneyhan

Reputation: 557

Something like this will work:

let highestLength = 0;
let highestItem = 0;
for (let i = 0; i < items.length; i++) {
  let objLength = Object.keys(items[i]).length;
  if (objLength > highestLength) {
    highestLength = objLength;
    highestItem = i;
  }
}

Then highestItem will hold the index of the first element with the highest number of keys.

Upvotes: 2

Related Questions