ZA-ITP-May-2025 | Christian Mayamba | Module-Data-Groups | Week 1

Sprint-1/implement/sum.js

@@ -1,4 +1,21 @@
 function sum(elements) {
+  if (elements.length === 0) {
+    return 0;
+  }
+
+  if (elements.every((item) => typeof item === "string")) {
+    return "undefined";
+  }
+
+  const numbersArray = elements.filter((item) => typeof item === "number");
+
+  let sum1 = 0;
+  for (let i = 0; i < numbersArray.length; i++) {
+    sum1 += numbersArray[i];
+  }
+  return sum1;
 }
+testVar = [10, "jesus", 20, "hi"];
+console.log(sum(testVar));
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -13,24 +13,41 @@ const sum = require("./sum.js");
 // Given an empty array
 // When passed to the sum function
 // Then it should return 0
-test.todo("given an empty array, returns 0")
+test("given an empty array, returns 0", () => {
+  expect(sum([])).toEqual(0);
+});
 
 // Given an array with just one number
 // When passed to the sum function
 // Then it should return that number
+test("given array with one number, returns that number", () => {
+  expect(sum([10])).toEqual(10);
+});
 
 // Given an array containing negative numbers
 // When passed to the sum function
 // Then it should still return the correct total sum
+test("given an array with negative numbers, returns the total sum", () => {
+  expect(sum([-10, -5, -50])).toEqual(-65);
+});
 
 // Given an array with decimal/float numbers
 // When passed to the sum function
 // Then it should return the correct total sum
+test("given an array with decimal numbers, returns the total sum", () => {
+  expect(sum([10.5, 65.9, 50.8])).toEqual(127.2);
+});
 
 // Given an array containing non-number values
 // When passed to the sum function
 // Then it should ignore the non-numerical values and return the sum of the numerical elements
+test("Non-numerical values should be ignored and return the sum of the rest", () => {
+  expect(sum(["hey", 10, "hi", 60, 10])).toEqual(80);
+});
 
 // Given an array with only non-number values
 // When passed to the sum function
 // Then it should return the least surprising value given how it behaves for all other inputs
+test("Only non-number values should return undefined", () => {
+  expect(sum(["hey", "love", "hi", "hate"])).toEqual("undefined");
+});