We can do this using Object.groupBy() method. This method groups elements of an object according to values returned from a callback function.

Example:

const users = [
    {
        name:"Sandeep",
        age:30
    },
    {
        name:"John",
        age:20
    },
    {
        name:"Virat",
        age:16
    },
    {
        name:"Lionel",
        age:35
    }
];

const result = Object.groupBy( users, ( { age } ) => {
    return age > 20 ? "adult" : "teen";
} );

console.log( result );

Output: