3.js

Author: enjoy15

Sprint-1/2-mandatory-errors/3.js

@@ -1,9 +1,11 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+const last4Digits = cardNumber.toString().slice(-4);
 
 // The last4Digits variable should store the last 4 digits of cardNumber
 // However, the code isn't working
-// Before running the code, make and explain a prediction about why the code won't work
-// Then run the code and see what error it gives.
-// Consider: Why does it give this error? Is this what I predicted? If not, what's different?
-// Then try updating the expression last4Digits is assigned to, in order to get the correct value
+// PREDICTION: The code won't work because cardNumber is a number, but .slice() only works on strings and arrays
+// ERROR: TypeError: cardNumber.slice is not a function
+// SOLUTION: Convert the number to a string first using .toString() method
+console.log(last4Digits); // Should output: "4213"
+//The issue is that cardNumber is a number, but the .slice() method only works on strings (and arrays).
+// Convert the number to a string first, then use .slice()