Glasgow | 25-ITP-SEP | Fares Bakhet | Sprint 1 | Coursework/sprint 1

Sprint-1/fix/median.js

@@ -6,9 +6,22 @@
 // or 'list' has mixed values (the function is expected to sort only numbers).
 
 function calculateMedian(list) {
-  const middleIndex = Math.floor(list.length / 2);
-  const median = list.splice(middleIndex, 1)[0];
-  return median;
+  // Make sure input is an array
+  if (!Array.isArray(list)) return null;
+
+  // Filter only valid numbers (exclude NaN, null, strings, etc.)
+  const numbers = list.filter((n) => typeof n === "number" && !isNaN(n));
+
+  if (numbers.length === 0) return null;
+
+  const mid = Math.floor(sorted.length / 2);
+
+  const sorted = numbers.sort((a, b) => a - b);
+
+  if (sorted.length % 2 === 0) {
+    return (sorted[mid - 1] + sorted[mid]) / 2;
+  }
+  return sorted[mid];
 }
 
 module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,6 @@
-function dedupe() {}
+function dedupe(arr) {
+  const deduplicates = arr.filter((item, index) => arr.indexOf(item) === index);
+  return deduplicates;
+}
+
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -16,12 +16,40 @@ E.g. dedupe([1, 2, 1]) target output: [1, 2]
 // Given an empty array
 // When passed to the dedupe function
 // Then it should return an empty array
-test.todo("given an empty array, it returns an empty array");
+test("given an empty array, it returns an empty array", () => {
+  [{ input: [], expected: [] }].forEach(({ input, expected }) => {
+    expect(dedupe(input)).toEqual(expected);
+  });
+});
 
 // Given an array with no duplicates
 // When passed to the dedupe function
 // Then it should return a copy of the original array
 
+test("given an array with no duplicates, it returns a copy of the original array", () => {
+  [
+    { input: [1, 2, 3], expected: [1, 2, 3] },
+    { input: ["a", "b", "c"], expected: ["a", "b", "c"] },
+    { input: [true, false], expected: [true, false] },
+  ].forEach(({ input, expected }) => {
+    const result = dedupe(input);
+
+    expect(dedupe(input)).toEqual(expected);
+    expect(result).not.toBe(input);
+
+  });
+});
+
 // Given an array with strings or numbers
 // When passed to the dedupe function
 // Then it should remove the duplicate values, preserving the first occurence of each element
+
+test("given an array with strings or numbers, it removes duplicate values preserving the first occurrence of each element", () => {
+  [
+    { input: [1, 2, 2, 3, 3, 3], expected: [1, 2, 3] },
+    { input: ["a", "b", "b", "c", "c", "c"], expected: ["a", "b", "c"] },
+    { input: [true, false, false, true], expected: [true, false] },
+  ].forEach(({ input, expected }) => {
+    expect(dedupe(input)).toEqual(expected);
+  });
+});

Sprint-1/implement/max.js

@@ -1,4 +1,13 @@
-function findMax(elements) {
+function findMax(arr) {
+  if (!Array.isArray(arr) || arr.length === 0) return -Infinity;
+
+  const numbers = arr.filter((n) => typeof n === "number" && !isNaN(n));
+
+  if (numbers.length > 0) {
+    return Math.max(...numbers);
+  }
+
+  return arr[arr.length - 1];
 }
 
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -16,28 +16,48 @@ 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([42])).toBe(42);
+});
 
 // 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 number", () => {
+  expect(findMax([30, -10, 50, -20, 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 one to zero", () => {
+  expect(findMax([-30, -10, -50, -20, -40])).toBe(-10);
+});
 
 // 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 decimal number", () => {
+  expect(findMax([3.5, 2.1, 4.8, 1.9])).toBe(4.8);
+});
 
 // 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 max and ignores non-numeric values", () => {
+  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(["a", "b", "c"])).toBe("c");
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,11 @@
 function sum(elements) {
+  let totalSum = 0;
+  for (let i = 0; i < elements.length; i++) {
+    if (typeof elements[i] === "number") {
+      totalSum += elements[i];
+    }
+  }
+  return totalSum;
 }
 
 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([])).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([42])).toBe(42);
+});
 
 // 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 containing negative numbers, returns the correct total sum", () => {
+  expect(sum([-1, -2, -3])).toBe(-6);
+});
 
 // 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 correct total sum", () => {
+  expect(sum([1.5, 2.5, 3.5])).toBeCloseTo(7.5);
+});
 
 // 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 numbers", () => {
+  expect(sum([10, "hello", 20, true, 30, null])).toBe(60);
+});
 
 // 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(["hello", true, null])).toBe(0);
+});

Sprint-1/refactor/includes.js

@@ -1,8 +1,17 @@
 // Refactor the implementation of includes to use a for...of loop
 
+// function includes(list, target) {
+//   for (let index = 0; index < list.length; index++) {
+//     const element = list[index];
+//     if (element === target) {
+//       return true;
+//     }
+//   }
+//   return false;
+// }
+
 function includes(list, target) {
-  for (let index = 0; index < list.length; index++) {
-    const element = list[index];
+  for (const element of list) {
     if (element === target) {
       return true;
     }