refactor toPounds function for improved input handling and output formatting

Author: zilinskyte

Sprint-2/3-mandatory-implement/3-to-pounds.js

@@ -1,6 +1,34 @@
 // In Sprint-1, there is a program written in interpret/to-pounds.js
-
 // You will need to take this code and turn it into a reusable block of code.
 // You will need to declare a function called toPounds with an appropriately named parameter.
-
 // You should call this function a number of times to check it works for different inputs
+
+function toPounds(penceString) {
+penceString = String(penceString);// ensures input is treated as a string even if number is inputted
+// const penceStringWithoutTrailingP = penceString.substring(
+let penceStringWithoutTrailingP = penceString;
+if (penceString.endsWith("p")) {
+    penceStringWithoutTrailingP = penceString.substring(0, penceString.length - 1);
+}   // This prevents the last characters from being sliced off if there is no p.
+
+const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+const pounds = paddedPenceNumberString.substring(
+  0,
+  paddedPenceNumberString.length - 2
+);
+
+const pence = paddedPenceNumberString
+  .substring(paddedPenceNumberString.length - 2)
+  .padEnd(2, "0");
+
+return`£${pounds}.${pence}`;
+}
+console.log(toPounds("481p"));
+console.log(toPounds("50p"));
+console.log(toPounds("5p"));
+console.log(toPounds("0p"));
+console.log(toPounds("12345p"));
+console.log(toPounds("9")); // edge case: missing 'p' at the end, returns 0 rather than error because last character is sliced off
+// Can be fixed by changing line 8 
+console.log(toPounds("abc")); // Works but returns nonsense value
+console.log(toPounds(123)); // Works with number input because of line 7 converting to string