Fix: 04-02 test case causes max call stack exceeded

04-recursion/02-unwinding/readme.md

@@ -10,8 +10,8 @@ Let's look at an example of this. Consider the following function:
 
 ```js
 function sumUpTo(n) {
-  if (n === 1) {
-    return 1;
+  if (n <= 1) {
+    return n;
   }
 
   return n + sumUpTo(n - 1);
@@ -50,9 +50,9 @@ We can see this by logging the function calls and the return values:
 
 ```js
 function sumUpTo(n) {
-  if (n === 1) {
+  if (n <= 1) {
     console.log(`sumUpTo(${n}) returns 1`);
-    return 1;
+    return n;
   }
 
   console.log(`sumUpTo(${n}) calls sumUpTo(${n - 1}) + ${n}`);

04-recursion/02-unwinding/sum-up-to-solution.js

@@ -1,7 +1,8 @@
 function sumUpTo(n) {
   // Base case - when n is 1, we return 1
-  if (n === 1) {
-    return 1;
+  // if n is 0 or negative, we handle that case otherwise infinite recursion
+  if (n <= 1) {
+    return n;
   }
 
   // Recursive case - when n is greater than 1, we return the sum of n and sumUpTo(n - 1)

04-recursion/02-unwinding/sum-up-to-test.js

@@ -1,3 +1,5 @@
+const sumUpTo = require('./sum-up-to');
+
 test('Summing up positive integers', () => {
   expect(sumUpTo(5)).toBe(15);
   expect(sumUpTo(10)).toBe(55);