For checking a student grade with percentage

gradScore function

const gradScore = (sScore, totalScore = 100) => {

  const score = Math.floor(sScore / 10);

  var grade = {
    10: 'A',
    9: 'A',
    8: 'B',
    7: 'C',
    6: 'D',
    5: 'F',
    4: 'F',
    3: 'F',
    2: 'F',
    1: 'F',
    0: 'F'
  } [score];

  return `You got ${grade} (${sScore}%)`;
};

let studantScore = gradScore(90);
console.log(studantScore);