Brussels | ITP-2026-1 | Meysam Razagh | Sprint-1 | All Exercises

Sprint-1/fix/median.js

@@ -1,14 +1,29 @@
-// Fix this implementation
-// Start by running the tests for this function
-// If you're in the Sprint-1 directory, you can run `npm test -- fix` to run the tests in the fix directory
+function calculateMedian(list) {
+  // Check if input is a valid array
+  if (!Array.isArray(list)) {
+    return null;
+  }
 
-// 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).
+  // Filter the list to keep only numbers
+  const numbers = list.filter((item) => typeof item === "number");
 
-function calculateMedian(list) {
-  const middleIndex = Math.floor(list.length / 2);
-  const median = list.splice(middleIndex, 1)[0];
-  return median;
-}
+  // Return null if no numbers are found
+  if (numbers.length === 0) {
+    return null;
+  }
+
+  // Sort the numbers in ascending order
+  // Note: we use [...numbers] or just numbers because filter already created a new array
+  numbers.sort((a, b) => a - b);
 
+  const middleIndex = Math.floor(numbers.length / 2);
+
+  // If the count of numbers is odd, return the middle one
+  if (numbers.length % 2 !== 0) {
+    return numbers[middleIndex];
+  }
+
+  // If the count is even, return the average of the two middle numbers
+  return (numbers[middleIndex - 1] + numbers[middleIndex]) / 2;
+}
 module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,18 @@
-function dedupe() {}
+function dedupe(elements) {
+  // Create a new empty array to store unique items
+  let uniqueItems = [];
+
+  // Loop through every item in the input array
+  for (let i = 0; i < elements.length; i++) {
+    // Check if the item is already in our uniqueItems array
+    if (!uniqueItems.includes(elements[i])) {
+      // If not present, add it to the uniqueItems array
+      uniqueItems.push(elements[i]);
+    }
+  }
+
+  // Return the final array without duplicates
+  return uniqueItems;
+}
+
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -1,27 +1,17 @@
 const dedupe = require("./dedupe.js");
-/*
-Dedupe Array
 
-📖 Dedupe means **deduplicate**
+test("given an empty array, it returns an empty array", () => {
+  // If input is empty, output should be empty
+  expect(dedupe([])).toEqual([]);
+});
 
-In this kata, you will need to deduplicate the elements of an array
+test("given an array with no duplicates, it returns a copy of the original array", () => {
+  // If there are no duplicates, the array stays the same
+  expect(dedupe([1, 2, 3])).toEqual([1, 2, 3]);
+});
 
-E.g. dedupe(['a','a','a','b','b','c']) target output: ['a','b','c']
-E.g. dedupe([5, 1, 1, 2, 3, 2, 5, 8]) target output: [5, 1, 2, 3, 8]
-E.g. dedupe([1, 2, 1]) target output: [1, 2]
-*/
-
-// Acceptance Criteria:
-
-// 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");
-
-// Given an array with no duplicates
-// When passed to the dedupe function
-// Then it should return a copy of the original array
-
-// 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", () => {
+  // Test if duplicates like 'a' or '1' are removed
+  expect(dedupe(["a", "a", "b"])).toEqual(["a", "b"]);
+  expect(dedupe([1, 1, 2, 2, 3])).toEqual([1, 2, 3]);
+});

Sprint-1/implement/max.js

@@ -1,4 +1,14 @@
 function findMax(elements) {
+  // First, we filter the list to keep ONLY numbers
+  const onlyNumbers = elements.filter((item) => typeof item === "number");
+
+  // If there are no numbers at all, we return -Infinity (standard math behavior)
+  if (onlyNumbers.length === 0) {
+    return -Infinity;
+  }
+
+  // Use Math.max with the spread operator (...) to find the largest number
+  return Math.max(...onlyNumbers);
 }
 
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -1,43 +1,36 @@
-/* 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.
-
-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)
-
-You should implement this function in max.js, and add tests for it in this file.
-
-We have set things up already so that this file can see your function from the other file.
-*/
-
 const findMax = require("./max.js");
 
-// Given an empty array
-// 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");
-
-// Given an array with one number
-// When passed to the max function
-// Then it should return that number
-
-// Given an array with both positive and negative numbers
-// When passed to the max function
-// Then it should return the largest number overall
-
-// Given an array with just negative numbers
-// When passed to the max function
-// Then it should return the closest one to zero
-
-// Given an array with decimal numbers
-// When passed to the max function
-// Then it should return the largest decimal number
-
-// Given an array with non-number values
-// When passed to the max function
-// Then it should return the max and ignore non-numeric values
-
-// 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 empty array, returns -Infinity", () => {
+  // Test case for empty input
+  expect(findMax([])).toBe(-Infinity);
+});
+
+test("given an array with one number, it returns that number", () => {
+  // Test case for single element
+  expect(findMax([5])).toBe(5);
+});
+
+test("given an array with both positive and negative numbers, it returns the largest", () => {
+  // Test case for mixed positive and negative numbers
+  expect(findMax([-1, 10, -5])).toBe(10);
+});
+
+test("given an array with just negative numbers, it returns the closest one to zero", () => {
+  // Test case for negative numbers
+  expect(findMax([-10, -1, -5])).toBe(-1);
+});
+
+test("given an array with decimal numbers, it returns the largest decimal number", () => {
+  // Test case for decimal numbers
+  expect(findMax([1.1, 1.5, 1.2])).toBe(1.5);
+});
+
+test("given an array with non-number values, it returns the max and ignores others", () => {
+  // Test case to ensure non-numeric values are ignored
+  expect(findMax([10, "hi", 20, null])).toBe(20);
+});
+
+test("given an array with only non-number values, it returns -Infinity", () => {
+  // Test case where no valid numbers exist in the array
+  expect(findMax(["a", "b", "c"])).toBe(-Infinity);
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,18 @@
 function sum(elements) {
+  // Start with a total of 0
+  let total = 0;
+
+  // Go through every item in the array one by one
+  for (let i = 0; i < elements.length; i++) {
+    // We only care about numbers, so we check the type
+    if (typeof elements[i] === "number") {
+      // Add the number to our total
+      total = total + elements[i];
+    }
+  }
+
+  // Return the final result
+  return total;
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -1,36 +1,26 @@
-/* Sum the numbers in an array
-
-In this kata, you will need to implement a function that sums the numerical elements of an array
-
-E.g. sum([10, 20, 30]), target output: 60
-E.g. sum(['hey', 10, 'hi', 60, 10]), target output: 80 (ignore any non-numerical elements)
-*/
-
 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")
+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 just one number, returns that number", () => {
+  expect(sum([10])).toBe(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 containing negative numbers, returns correct total", () => {
+  expect(sum([10, -5, 5])).toBe(10);
+});
 
-// 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 correct total", () => {
+  expect(sum([1.5, 2.5, 1])).toBe(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", () => {
+  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", () => {
+  // 0 is the 'least surprising value' since it's the starting point
+  expect(sum(["apple", "orange"])).toBe(0);
+});

Sprint-1/refactor/includes.js

@@ -1,8 +1,7 @@
-// Refactor the implementation of includes to use a for...of loop
-
+// This function checks if the target exists in the list
 function includes(list, target) {
-  for (let index = 0; index < list.length; index++) {
-    const element = list[index];
+  // We use for...of for a cleaner syntax (refactoring)
+  for (const element of list) {
     if (element === target) {
       return true;
     }

Sprint-1/refactor/includes.test.js

@@ -1,5 +1,3 @@
-// Refactored version of includes should still pass the tests below:
-
 const includes = require("./includes.js");
 
 test("returns true when target is in array", () => {