wrote the implemention and test cases for max.js in sprint-1

Author: fayaz551

Sprint-1/implement/max.js

@@ -1,4 +1,26 @@
 function findMax(elements) {
+  if (!Array.isArray(elements)) {
+    return null;
+  }
+
+  // If the array is truly empty, return -Infinity
+  if (elements.length === 0) {
+    return -Infinity;
+  }
+
+  // Filter only numeric values
+  const numbers = elements.filter(function (item) {
+    return typeof item === "number" && !isNaN(item);
+  });
+
+  // If there are no numeric values but the array wasn't empty, return null
+  if (numbers.length === 0) {
+    return null;
+  }
+
+  // Otherwise, return the largest number
+  return Math.max.apply(null, numbers);
 }
 
 module.exports = findMax;
+

Sprint-1/implement/max.test.js

@@ -16,28 +16,49 @@ const findMax = require("./max.js");
 // When passed to the max function
 // Then it should return -Infinity
 // Delete this test.todo and replace it with a test.
-test.todo("given an empty array, returns -Infinity");
+test("given an empty array, returns -Infinity", () => {
+  expect(findMax([])).toBe(-Infinity);
+});
+
 
 // Given an array with one number
 // When passed to the max function
 // Then it should return that number
+test("given an array with one number, returns that number", () => {
+  expect(findMax([5])).toBe(5);
+});
 
 // Given an array with both positive and negative numbers
 // When passed to the max function
 // Then it should return the largest number overall
+test("given an array with both positive and negative numbers, returns the largest", () => {
+  expect(findMax([30, 50, 10, 40])).toBe(50);
+});
 
 // Given an array with just negative numbers
 // When passed to the max function
 // Then it should return the closest one to zero
+test("given an array with just negative numbers, returns the closest to zero", () => {
+  expect(findMax([-10, -5, -20])).toBe(-5);
+});
 
 // Given an array with decimal numbers
 // When passed to the max function
 // Then it should return the largest decimal number
+test("given an array with decimal numbers, returns the largest", () => {
+  expect(findMax([3.14, 2.71, 1.41])).toBe(3.14);
+});
 
 // Given an array with non-number values
 // When passed to the max function
 // Then it should return the max and ignore non-numeric values
+test("given an array with non-number values, returns the largest number", () => {
+  expect(findMax(['hey', 10, 'hi', 60, 10])).toBe(60);
+});
 
 // Given an array with only non-number values
 // When passed to the max 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 the least surprising value", () => {
+  expect(findMax(['hey', 'hi', 'hello'])).toBe(null);
+});