fix(sprint-2): resolve convertToPercentage errors with proper scoping and declaration

Author: Tarawally

Sprint-2/1-key-errors/1.js

@@ -2,19 +2,24 @@
 
 // Why will an error occur when this program runs?
 // =============> write your prediction here
+// SyntaxError: Cannot redeclare parameter 'decimalNumber' inside function body
 
 // Try playing computer with the example to work out what is going on
 
-function convertToPercentage(decimalNumber) {
-  const decimalNumber = 0.5;
-  const percentage = `${decimalNumber * 100}%`;
-
-  return percentage;
-}
-
-console.log(decimalNumber);
+// function convertToPercentage(decimalNumber) {
+//   const decimalNumber = 0.5;
+//   const percentage = `${decimalNumber * 100}%`;
+//   return percentage;
+// }
+// console.log(decimalNumber);
 
 // =============> write your explanation here
+// SyntaxError: Identifier 'decimalNumber' has already been declared - parameter cannot be redeclared
+// Also, console.log(decimalNumber) would cause ReferenceError - variable only exists inside function scope
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Errors/Redeclared_parameter
 
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+function convertToPercentage(decimalNumber) {
+  return `${decimalNumber * 100}%`;
+}