Prime Pairs JS

function primePairs(input) {
    let startFirstCouple = Number(input[0]);
    let startSecondCouple = Number(input[1]);
    let diffFirstCouple = Number(input[2]);
    let diffSecondCouple = Number(input[3]);

    let endFirstCouple = startFirstCouple + diffFirstCouple;
    let endSecondCouple = startSecondCouple + diffSecondCouple;

    for (let i = startFirstCouple; i <= endFirstCouple; i++) {
        for (let j = startSecondCouple; j <= endSecondCouple; j++) {

        let isPrime1 = true;
        let isPrime2 = true;

        for (k = 2; k < i; k++) {
            if (i % k === 0) {
                isPrime1 = false;
                break;
            }
        }
            for (let l = 2; l < j; l++) {
                if (j % l === 0) {
                    isPrime2 = false;
                    break;
                }
            }
            if (isPrime1 && isPrime2) {
                primeCouple = `${i}${j}`
                console.log(primeCouple);
            }
        }
    }
}