In 1-key-errors, deleted unwanted variable, and console.log function with parameter

Author: TzeMingHo

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

@@ -1,10 +1,18 @@
 // Predict and explain first...
+// At the first glance, I believe the function would occur errors because the variable decimalNumber is declared twice.
+// Besides, console.log is trying to log a variable that is not defined in global scope.
 
 // Why will an error occur when this program runs?
 // =============> write your prediction here
+// The first error should be a syntax error that "decimalNumber" has already been declared.
+// Since decimalNumber is declared as a parameter of the function,
+// when a new variable also named decimalNumber is declared inside the function,
+// it causes a conflict.
 
-// Try playing computer with the example to work out what is going on
+// The second error should be a reference error that "decimalNumber is not defined".
 
+// Try playing computer with the example to work out what is going on
+/*
 function convertToPercentage(decimalNumber) {
   const decimalNumber = 0.5;
   const percentage = `${decimalNumber * 100}%`;
@@ -13,8 +21,19 @@ function convertToPercentage(decimalNumber) {
 }
 
 console.log(decimalNumber);
+*/
 
 // =============> write your explanation here
+// After running the code, I got a syntax error that "decimalNumber" has already been declared.
+// I also found out that the decimalNumber inside the function should be declared again.
+// Besides, if we want to log the result of the function, we should call the function with an argument inside console.log().
 
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+function convertToPercentage(decimalNumber) {
+  const percentage = `${decimalNumber * 100}%`;
+
+  return percentage;
+}
+console.log(convertToPercentage(0.5)); // should return "50%"
+console.log(convertToPercentage(0.75)); // should return "75%"