Javascript: Finding largest value in object array and returning the key [duplicate]

Question

I need to write a code that will look through the data array, and return the name of the oldest person.

console.log('The oldest person is ${oldestPerson}.')


let data = {
    {
        name: Henry,
        age: 20,
        job: 'store clerk'
    },
    {
        name: Juliet,
        age: 18,
        job: 'student'
    },
    {
        name: Luna,
        age: 47,
        job: 'CEO'
    },

So far, I'm able to return separate arrays containing the names and ages, but I'm not sure how to find the oldest age and return name of the oldest person.

let names = data.map((person) => {
    return person.name
});

let ages = data.map((person) => {
    return Math.max(person.age)
});

sort the list and take the first one?

castis
– castis

2019-02-13 18:52:04 +00:00
Commented Feb 13, 2019 at 18:52 — castis
– castis, Commented Feb 13, 2019 at 18:52

ellipsis · Accepted Answer · 2019-02-13 18:59:23Z

2

Using reduce

let data = [{
    name: ' Henry',
    age: 20,
    job: 'store clerk'
  },
  {
    name: 'Juliet',
    age: 18,
    job: 'student'
  },
  {
    name: 'Luna',
    age: 47,
    job: 'CEO'
  }
];
var max = 0;
console.log(data.reduce((acc, a) => {
  if (a.age > max) {
    acc = a.name
    max = a.age;
  }
  return acc;
}, ""))

edited Feb 13, 2019 at 18:59

answered Feb 13, 2019 at 18:53

ellipsis

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4 Comments

Adam Jenkins Over a year ago

That logs the age, not the name :)

ellipsis Over a year ago

thanks mate for pointing that

lebookworm Over a year ago

Thank you both for the help! I'm new at this and wouldn't have thought to use .reduce. Reading up more on it now. Thanks again.

ellipsis Over a year ago

If it helped you upvote and mark it as correct so it can help others too

Adam Jenkins · Accepted Answer · 2022-10-19 09:56:02Z

2

To get the max age, you've got no choice but to loop over the entire array (and get the oldest one). So while you're looping over the array, grab the name too.

This is one approach of many:

let highestAge = 0;
const oldestName = data.reduce((prev,curr) => {
  if(curr.age > highestAgo) {
    highestAge = curr.age;
    return curr.name;
  }
  return prev;
},'');

edited Oct 19, 2022 at 9:56

answered Feb 13, 2019 at 18:51

Adam Jenkins

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