Converted toString before using slice, in 3.js

Author: habohlin

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

@@ -1,9 +1,25 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+const last4Digits = cardNumber.toString().slice(-4);
+console.log(last4Digits);
 
 // 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: I believe slice counts forward from the start when you use positive values, and
+// backwards from the end when you use negative. So if you only put in one negative number, it's counts
+// backward from the end to the last 4, but can't "turn around" to count up to the end again..?
+
+// After running the code: The actual error was a TypeError, saying that cardNumber.slice is not a function.
+// That means you can't put anything in parenthesis after cardNumber.slice. However, when I used slice before
+// slice definitely takes parameters. This made me think about the fact that cardNumber is actually a
+// number, and slice is probably only for strings or arrays. You can't really count positions in a number.
+
+// I solved it by chaining a toString before slicing. My initial theory was completely wrong, putting a
+// negative number in slice is completely fine. Now last4Digits is a string, not a number. But it seems
+// easier to work with as a string, if specific digits need to be accessed, so I will keep it as a string.