Arrays and Objects in JS

Given an input array which stores names and respective age as an object, how can one group these objects into respective age groups.

Problem Statement

//Example Input : 
let people = [
  { name: "sumit", age: 17 },
  { name: "rajesh", age: 24 },
  { name: "akbar", age: 44 },
  { name: "ali", age: 44 },
];
//Expected Output:
[
  { '17': [ { name: "sumit", age: 17 } ] },
  { '24': [ { name: "rajesh", age: 24 } ] },
  { '44': [ { name: "akbar", age: 44 }, 
            { name: "ali", age: 44 }, ] }
] 

Highlights / Explanation:

• First task here is to identify the structural pattern of the result set - Clearly these Objects are enclosed in an array for every age group and the age group is an object enclosed in the resultant array.

• Secondly, we need to loop through the objects in the input array to group individuals by age group by looking up the result array
  

let people = [
  { name: "sumit", age: 17 },
  { name: "rajesh", age: 24 },
  { name: "akbar", age: 44 },
  { name: "ali", age: 44 },
];

let index = -1,
  age;

let result = people.reduce((acc, ele) => {
  age = ele.age;
  index = acc.findIndex((ele) => Object.keys(ele).toString() == age);
  if (index == -1) {
    acc.push({ [age]: [].concat(ele) });
  } else {
    acc[index][age].push(ele);
  }
  return acc;
}, []);

console.log(result);