Update repeat-str.js

Author: joanne342

Sprint-3/2-practice-tdd/repeat-str.js

@@ -4,9 +4,12 @@ function repeatStr() {
   if (count === 1) {
     return str;
 
-  } else if (count < 1) {
+  } else if (count < 0) {
     throw new Error("Something went wrong");
 
+  } else if (count === 0) {
+    return "";
+
   } else {
     return Array.from({ length: count }, () => str).join("");
   }