Exercice 1.2.3 : apprendre les particularités du switch et l'utilisation de la bibliothèque standard

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var shortenBytes = '10t'; 
var letter = shortenBytes.substr(-1, 1); 
var bytes; 
var number = Number.parseInt(shortenBytes, 10); 
 
//console.log(letter)  

if (isNaN(number)){
    bytes =  false
}else if (number != isNaN){

switch (letter.toUpperCase()) { 
    case 'K':
        bytes = number * 1024;
        break;
    case 'M':
        bytes = number * 1024 * 1024;
        break;
    case 'G':
        bytes = number * 1024 * 1024 * 1024;
        break;
    case 'T':
        bytes = number * 1024 * 1024 * 1024 * 1024;
        break;
    default:
        bytes = false; 
} 
}
  
console.log(bytes);

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var nombreUniteMesure = '150';
var nombre = nombreUniteMesure.substr(0,--nombreUniteMesure.length);
var number = +nombre; 
var uniteMesure = nombreUniteMesure.substr(-1,1);
switch (uniteMesure.toUpperCase()){ 
    case ' '://"Si on n'indique pas d'unité', on suppose que la var testée indique des octets"
    result = number;
    break;
  case 'K':
    result = number*1024;
    break;
  case 'M':
    result = number*Math.pow(1024,2);
    break; 
  case 'G':
    result = number*Math.pow(1024,3);
    break;   
  case 'T':
    result = number*Math.pow(1024,4);
    break;  
  default:
    result=(!true)
}
console.log(result);