scoreTest.js

/*
The first input array contains the correct answers to an exam, like ["a", "a", "b", "d"]. The second one is "answers" array and contains student's answers.

The two arrays are not empty and are the same length. Return the score for this array of answers, giving +4 for each correct answer, -1 for each incorrect answer, and +0 for each blank answer(empty string).

If the score < 0, return 0.

For example:

checkExam(["a", "a", "b", "b"], ["a", "c", "b", "d"]) → 6
checkExam(["a", "a", "c", "b"], ["a", "a", "b",  ""]) → 7
checkExam(["a", "a", "b", "c"], ["a", "a", "b", "c"]) → 16
checkExam(["b", "c", "b", "a"], ["",  "a", "a", "c"]) → 0
*/

//Answer//

function checkExam(a1, a2) {
let correct = 0
a2.forEach((x,i)=>{if (x===a1[i]){correct+=4}else if(x===''){correct+=0}else{correct-=1}})
return correct<0?0:correct
}