Added tests and implemented solution for the implement section - sum.js and sum.test.js

Author: Konvaly

Sprint-1/implement/sum.js

@@ -1,4 +1,19 @@
 function sum(elements) {
+  const numbers = elements.filter(
+    (item) => typeof item === "number" && !isNaN(item)
+  );
+
+  if (numbers.length === 0) return 0;
+
+  const maxDecimalPlaces = numbers.reduce(
+    (currMax, el) => Math.max(currMax, (String(el).split(".") || "").length),
+    0
+  );
+  const decMultiplier = 10 ** maxDecimalPlaces;
+
+  const total = numbers.reduce((acc, el) => acc + el, 0);
+
+  return Math.round((total + Number.EPSILON) * decMultiplier) / decMultiplier;
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -9,28 +9,46 @@ E.g. sum(['hey', 10, 'hi', 60, 10]), target output: 80 (ignore any non-numerical
 const sum = require("./sum.js");
 
 // Acceptance Criteria:
-
-// Given an empty array
-// When passed to the sum function
-// Then it should return 0
-test.todo("given an empty array, returns 0")
-
-// Given an array with just one number
-// When passed to the sum function
-// Then it should return that number
-
-// Given an array containing negative numbers
-// When passed to the sum function
-// Then it should still return the correct total sum
-
-// Given an array with decimal/float numbers
-// When passed to the sum function
-// Then it should return the correct total sum
-
-// 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
-
-// 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
+describe("sum", () => {
+  // Given an empty array
+  // When passed to the sum function
+  // Then it should return 0
+  test("given an empty array, returns 0", () => {
+    expect(sum([])).toBe(0);
+  });
+
+  // Given an array with just one number
+  // When passed to the sum function
+  // Then it should return that number
+  test("given an array with one number, returns that number", () => {
+    expect(sum([15])).toBe(15);
+  });
+
+  // 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 correct sum", () => {
+    expect(sum([10, -6, 18, -10])).toBe(12);
+  });
+
+  // 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/float numbers, returns the correct total sum", () => {
+    expect(sum([65.5, 8.45, 32.4, 97.36, 10])).toBe(213.71);
+  });
+
+  // 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("given an array with non-number values, ignores them and returns the sum of numerical elements", () => {
+    expect(sum([10, "hello", 25, null, 5, undefined, {}, 15])).toBe(55);
+  });
+
+  // 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("given an array with only non-number values, returns 0", () => {
+    expect(sum(["Great!", "hi", null, undefined, {}, []])).toBe(0);
+  });
+});