fix: throw if average called with empty array

flowup · Jun 17, 2024 · 6f91ba2 · 6f91ba2
1 parent 52a0f31
commit 6f91ba2
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diff --git a/src/index.js b/src/index.js
@@ -13,6 +13,9 @@ export function sum(values) {
  * @returns {number} Average of all numbers.
  */
 export function average(values) {
+  if (values.length === 0) {
+    throw new Error('Cannot calculate average from empty array');
+  }
   return sum(values) / values.length;
 }
 

diff --git a/test/index.test.js b/test/index.test.js
@@ -16,6 +16,13 @@ describe('average', () => {
   it('should calculate average', () => {
     assert.strictEqual(average([1, 2, 3, 4]), 2.5);
   });
+
+  it('should throw for empty array', () => {
+    assert.throws(
+      () => average([]),
+      'Cannot calculate average for empty array'
+    );
+  });
 });
 
 describe('sort', () => {