group_by

group_by.js

let grouped = cars.reduce( 
    (groups, curr) => {
	     let key = curr.make;
         if (groups[key]===undefined) {
		     groups[key] = {count:1, minPrice:curr.price, maxPrice: curr.price };
   	     } else {
	   	     groups[key].count++;
	   	     groups[key].minPrice = Math.min(groups[key].minPrice, curr.price);
	   	     groups[key].maxPrice = Math.max(groups[key].maxPrice, curr.price);	   	     
   	     }
   	     return groups;
   	},
   	{}
);                                               

// RESULT IS
{
    Ferrari: {
        count: 5,
        minPrice: 262000,
        maxPrice: 336000
    },
    Lamborghini: {
        count: 1,
        minPrice: 329400,
        maxPrice: 329400
    },
    Bugatti: {
        count: 2,
        minPrice: 3000000,
        maxPrice: 3000000
    },
    McLaren: {
        count: 1,
        minPrice: 203000,
        maxPrice: 203000
    }
}