This code creates a function which will take an input of number "n" and return the number of pairs of socks a person has. The sockMerchant function will loop through the array of socks and keep track of how many pairs of socks each sock element has. If the sock element has a value of 1, then the sockMerchant function will add 1 to the value of the socks[element] variable. The function will also keep track of how many pairs of socks there are. If the value of the socks[element] variable is equal to 2, then the function will increment the number of pairs by 1.
function sockMerchant(n, ar) {
let socks = {};
let pairs = 0;
for (let element of ar) {
socks[element] = socks[element] + 1 || 1;
if (socks[element] % 2 === 0) {
pairs += 1;
}
}
return pairs;
}