Untitled

# How to convert a score point to a letter grade

A function that contains a switch iteration that has to be executed everytime the function is invoked:
```javascript
function convertScoreToGrade(score) {
  switch (true) {
    case score <= 100 && score >= 90:
      return 'A'
      break;
    case score <= 89 && score >= 80:
      return 'B'
      break;
    case score <= 79 && score >= 70:
      return 'C'
      break;
    case score <= 69 && score >= 60:
      return 'D'
      break;
    case score <= 59 && score >= 0:
      return 'F'
      break;
    default:
      return 'INVALID SCORE'
      break;
  }
}

convertScoreToGrade(91); // 'A'
convertScoreToGrade(76); // 'C'
```

Create an object once, where the function can retreive the letter grade according to the key being passed:
```javascript
let scoresArray = Array.from({ length: 101 }, (_, i) => i);
let scoresObject = scoresArray.reduce((obj, score) => {
  switch (true) {
    case score <= 100 && score >= 90:
      obj[score] = "A";
      return obj;
    case score <= 89 && score >= 80:
      obj[score] = "B";
      return obj;
    case score <= 79 && score >= 70:
      obj[score] = "C";
      return obj;
    case score <= 69 && score >= 60:
      obj[score] = "D";
      return obj;
    case score <= 59 && score >= 0:
      obj[score] = "F";
      return obj;
  }
}, {});

/*
{ 0: 'F',
  1: 'F',
  2: 'F',
  3: 'F',
  4: 'F',
  5: 'F',
  6: 'F',
  7: 'F',
  8: 'F',
  9: 'F',
  10: 'F',
  11: 'F',
  12: 'F',
  13: 'F',
  14: 'F',
  15: 'F',
  16: 'F',
  17: 'F',
  18: 'F',
  19: 'F',
  20: 'F',
  21: 'F',
  22: 'F',
  23: 'F',
  24: 'F',
  25: 'F',
  26: 'F',
  27: 'F',
  28: 'F',
  29: 'F',
  30: 'F',
  31: 'F',
  32: 'F',
  33: 'F',
  34: 'F',
  35: 'F',
  36: 'F',
  37: 'F',
  38: 'F',
  39: 'F',
  40: 'F',
  41: 'F',
  42: 'F',
  43: 'F',
  44: 'F',
  45: 'F',
  46: 'F',
  47: 'F',
  48: 'F',
  49: 'F',
  50: 'F',
  51: 'F',
  52: 'F',
  53: 'F',
  54: 'F',
  55: 'F',
  56: 'F',
  57: 'F',
  58: 'F',
  59: 'F',
  60: 'D',
  61: 'D',
  62: 'D',
  63: 'D',
  64: 'D',
  65: 'D',
  66: 'D',
  67: 'D',
  68: 'D',
  69: 'D',
  70: 'C',
  71: 'C',
  72: 'C',
  73: 'C',
  74: 'C',
  75: 'C',
  76: 'C',
  77: 'C',
  78: 'C',
  79: 'C',
  80: 'B',
  81: 'B',
  82: 'B',
  83: 'B',
  84: 'B',
  85: 'B',
  86: 'B',
  87: 'B',
  88: 'B',
  89: 'B',
  90: 'A',
  91: 'A',
  92: 'A',
  93: 'A',
  94: 'A',
  95: 'A',
  96: 'A',
  97: 'A',
  98: 'A',
  99: 'A',
  100: 'A' }
*/

function convertScoreToGrade(score) {
  return !scoresObject[score] ? "INVALID SCORE" : scoresObject[score];
}

convertScoreToGrade(99); // 'A'
convertScoreToGrade(81); // 'B'
convertScoreToGrade(-2); // 'INVALID SCORE'
```