Brussels | ITP-2026-1 | Benjamin Vanderzeypen | Sprint 1 | Week 7

Sprint-1/fix/median.js

@@ -5,10 +5,45 @@
 // Hint: Please consider scenarios when 'list' doesn't have numbers (the function is expected to return null)
 // or 'list' has mixed values (the function is expected to sort only numbers).
 
+// function calculateMedian(list) {
+//   const middleIndex = Math.floor(list.length / 2); // Finds the middle index of the array (rounds down if even)
+//   const median = list.splice(middleIndex, 1)[0]; // Removes the value at the middle index from the array and gets that value
+//   return median; // Returns the value found above as the median
+// }
+
 function calculateMedian(list) {
-  const middleIndex = Math.floor(list.length / 2);
-  const median = list.splice(middleIndex, 1)[0];
-  return median;
+  if (!Array.isArray(list)) {
+    // We first check if the array is indeed an array.
+    return null;
+  }
+
+  let numbers = [];
+  for (let i = 0; i < list.length; i++) {
+    if (typeof list[i] === "number") {
+      // Checks if the item in the array is a number, if so, push it to the numbers array.
+      numbers.push(list[i]);
+    }
+  }
+  if (numbers.length === 0) {
+    // This part checks if the numbers array we created is empty. If so, we return null.
+    return null;
+  }
+
+  let sorted = numbers.slice();
+  sorted.sort(function (a, b) {
+    // sorted is the sorted version of the numbers array. We created a new array so we don't lose the original.
+    return a - b;
+  });
+
+  let numbersAmount = sorted.length;
+  if (numbersAmount % 2 === 1) {
+    // Checks if the numbers in the array is odd. For example 3 numbers in the array.
+    return sorted[Math.floor(n / 2)]; // Returns the middle number of the array. We count from 0 so for example 0, 1, "2", 3, 4.
+  } else {
+    let mid1 = sorted[n / 2 - 1];
+    let mid2 = sorted[n / 2];
+    return (mid1 + mid2) / 2; // We take the two middle numbers avarege with divide by 2 to get the median.
+  }
 }
 
 module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,13 @@
-function dedupe() {}
+function dedupe(list) {
+  let result = [];
+
+  for (let i = 0; i < list.length; i++) {
+    if (!result.includes(list[i])) {
+      result.push(list[i]);
+    }
+  }
+
+  return result;
+}
+
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -16,12 +16,32 @@ 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", () => {
+  expect(dedupe([])).toEqual([]);
+});
 
 // 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", () => {
+  expect(dedupe([1, 2, 3])).toEqual([1, 2, 3]);
+});
 
 // 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
+
+// Duplicated strings.
+test("given an array of duplicate strings, it removes duplicates and keeps the first occurrence", () => {
+  expect(dedupe(["a", "a", "a", "b", "b", "c"])).toEqual(["a", "b", "c"]);
+});
+
+// Duplicated numbers.
+test("given an array of duplicate numbers, it removes duplicates and keeps the first occurrence", () => {
+  expect(dedupe([5, 1, 1, 2, 3, 2, 5, 8])).toEqual([5, 1, 2, 3, 8]);
+});
+
+// Mixed vanlues of numbers and strings.
+test("given a mixed array with duplicates, it preserves the first occurrence of each element", () => {
+  expect(dedupe([1, "a", 1, "a", 2, "b", 2])).toEqual([1, "a", 2, "b"]);
+});

Sprint-1/implement/max.js

@@ -1,4 +1,15 @@
-function findMax(elements) {
+function findMax(arrayElements) {
+  let max = -Infinity; // define max first, if the array is empty, return -Infinity
+  for (i = 0; i < arrayElements.length; i++) {
+    if (typeof arrayElements[i] === "number") {
+      // first checks if the array element is a number before moving on.
+      if (arrayElements[i] > max) {
+        // Finds the largest number after the === numbers test.
+        max = arrayElements[i]; // redefine max with the maximum number in the array.
+      }
+    }
+  }
+  return max;
 }
 
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -1,9 +1,9 @@
 /* Find the maximum element of an array of numbers
 
-In this kata, you will need to implement a function that find the largest numerical element of an array.
+In this kata, you will need to implement a function that finds the largest numerical element of an array.
 
 E.g. max([30, 50, 10, 40]), target output: 50
-E.g. max(['hey', 10, 'hi', 60, 10]), target output: 60 (sum ignores any non-numerical elements)
+E.g. max(['hey', 10, 'hi', 60, 10]), target output: 60 (max ignores any non-numerical elements)
 
 You should implement this function in max.js, and add tests for it in this file.
 
@@ -16,28 +16,59 @@ 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([44])).toBe(44);
+});
+
 // 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 overall", () => {
+  expect(findMax([-10, 0, 5, 30, -40])).toBe(30);
+});
+
 // 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 only negative numbers, returns the number closest to zero", () => {
+  expect(findMax([-20, -4, -43, -33, -7])).toBe(-4);
+});
+
 // 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([2.3, 4.4, 5.5, 1.2, 6.6])).toBe(6.6);
+});
+
 // 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 number and ignores non-numeric values", () => {
+  expect(findMax(["Spongebob", 2, "Squarepants", 5, 8, "patrick", 20])).toBe(
+    20
+  );
+});
+
 // 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-numeric values, returns -Infinity", () => {
+  expect(findMax(["Spongebob", "Squarepants", null, undefined])).toBe(
+    -Infinity
+  );
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,13 @@
 function sum(elements) {
+  let total = 0;
+
+  for (let i = 0; i < elements.length; i++) {
+    if (typeof elements[i] === "number") {
+      total = total + elements[i];
+    }
+  }
+
+  return total;
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -13,24 +13,47 @@ 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([44])).toBe(44);
+});
+
 // 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([-10, 5, -3, 8])).toBe(0);
+});
+
 // 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])).toBe(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 containing non-number values, ignores them and returns the sum of numbers", () => {
+  expect(sum(["hey", 10, "hi", 60, 10])).toBe(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("given an array with only non-number values, returns 0", () => {
+  expect(sum(["hello", null, undefined, "banana"])).toBe(0);
+});

Sprint-1/refactor/includes.js

@@ -1,8 +1,8 @@
 // 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];
+  for (const element of list) {
+    // const element = list[index]; => We don't need this line of code when using the for...of loop.
     if (element === target) {
       return true;
     }