London | 25-ITP-Sep| Sophia Mohamed | Sprint 1 | Sprint 1 Coursework

Sprint-1/fix/median.js

@@ -5,10 +5,24 @@
 // 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).
 
+// median.js
 function calculateMedian(list) {
-  const middleIndex = Math.floor(list.length / 2);
-  const median = list.splice(middleIndex, 1)[0];
-  return median;
+  if (!Array.isArray(list) || list.length === 0) return null;
+
+  const numbers = list.filter((item) => typeof item === "number");
+  if (numbers.length === 0) return null;
+
+  // Only ONE array — this sort does not mutate the original list
+  numbers.sort((a, b) => a - b);
+
+  const middle = Math.floor(numbers.length / 2);
+
+  if (numbers.length % 2 === 0) {
+    return (numbers[middle - 1] + numbers[middle]) / 2;
+  }
+
+  return numbers[middle];
 }
 
-module.exports = calculateMedian;
+
+module.exports = calculateMedian;

Sprint-1/fix/median.test.js

@@ -48,3 +48,6 @@ describe("calculateMedian", () => {
     it(`filters out non-numeric values and calculates the median for [${input}]`, () => expect(calculateMedian(input)).toEqual(expected))
   );
 });
+
+
+

Sprint-1/fix/package.json

@@ -0,0 +1,14 @@
+{
+  "name": "cyf-sprint-1",
+  "version": "1.0.0",
+  "description": "Sprint 1 solutions",
+  "main": "index.js",
+  "scripts": {
+    "test": "jest"
+  },
+  "devDependencies": {
+    "jest": "^29.0.0"
+  },
+  "author": "",
+  "license": "MIT"
+}

Sprint-1/implement/dedupe.js

@@ -1 +1,16 @@
-function dedupe() {}
+function dedupe(arr) {
+  const result = []; // This empty array will store unique items
+  const seen = new Set(); // Used to track what we've already seen
+
+  for (let item of arr) {
+    if (!seen.has(item)) {
+      seen.add(item);
+      result.push(item);
+    }
+  }
+
+  return result;
+}
+
+module.exports = dedupe;
+

Sprint-1/implement/dedupe.test.js

@@ -1,27 +1,37 @@
 const dedupe = require("./dedupe.js");
+
 /*
 Dedupe Array
+Dedupe = remove duplicates while keeping the first occurrence
+*/
 
-📖 Dedupe means **deduplicate**
+// TEST 1 — empty array
+test("given an empty array, it returns an empty array", () => {
+  expect(dedupe([])).toEqual([]);
+});
 
-In this kata, you will need to deduplicate the elements of an array
+// TEST 2 — no duplicates (should return a copy)
+test("given an array with no duplicates, it returns a copy of the array", () => {
+  const arr = [1, 2, 3, 4];
+  const result = dedupe(arr);
 
-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]
-*/
+  expect(result).toEqual([1, 2, 3, 4]);
+  expect(result).not.toBe(arr); // important check
+});
 
-// Acceptance Criteria:
+// TEST 3 — removes duplicates
+test("given an array with duplicates, it removes duplicates and preserves first occurrence", () => {
+  expect(dedupe(['a', 'a', 'b', 'c', 'c'])).toEqual(['a', 'b', 'c']);
+  expect(dedupe([5, 1, 1, 2, 3, 2, 5, 8])).toEqual([5, 1, 2, 3, 8]);
+  expect(dedupe([1, 2, 1])).toEqual([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 4 — should not mutate original array
+test("does not mutate the original array", () => {
+  const arr = [1, 1, 2, 3];
+  const copy = [...arr];
 
-// Given an array with no duplicates
-// When passed to the dedupe function
-// Then it should return a copy of the original array
+  dedupe(arr);
 
-// 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
+  expect(arr).toEqual(copy); // original unchanged
+});

Sprint-1/implement/max.js

@@ -1,4 +1,24 @@
 function findMax(elements) {
+  // If it's not an array, we can't process it
+  if (!Array.isArray(elements)) {
+    return null;
+  }
+
+  // Given an empty array, return -Infinity
+  if (elements.length === 0) {
+    return -Infinity;
+  }
+
+  // Keep only numeric values
+  const numericValues = elements.filter((el) => typeof el === "number");
+
+  // If there are no numeric values at all, return null
+  if (numericValues.length === 0) {
+    return null;
+  }
+
+  // Return the largest number (works for positive, negative, decimals)
+  return Math.max(...numericValues);
 }
 
-module.exports = findMax;
+module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -16,28 +16,54 @@ 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, it returns -Infinity", () => {
+  expect(findMax([])).toBe(-Infinity);
+});
+
 
 // Given an array with one number
 // When passed to the max function
-// Then it should return that number
-
+// 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 overall", () => {
+  expect(findMax([-10, 0, 10, 20, -5])).toBe(20);
+});
 // 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, -20, -5])).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 decimal number", () => {
+  expect(findMax([1.5, 2.3, 0.7, 2.9])).toBe(2.9);
+});
 // 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([10, "hello", 20, null, 15, undefined, "30"])).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-number values, returns null", () => {
+  expect(findMax(["a", "b", "c"])).toBeNull();
+});
+
+test("given an array with just negative numbers, returns the closest one to zero", () => {
+  expect(findMax([-20, -5, -15, -1])).toBe(-1);
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,19 @@
-function sum(elements) {
+
+function sum(arr) {
+  // If not an array, return 0 safely
+  if (!Array.isArray(arr)) return 0;
+
+  let total = 0;
+
+  for (let item of arr) {
+    if (typeof item === "number" && !isNaN(item)) {
+      total += item;
+    }
+  }
+
+  return total;
 }
 
 module.exports = sum;
+
+

Sprint-1/implement/sum.test.js

@@ -13,24 +13,49 @@ 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 one number, return 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 negative numbers, returns correct total", () => {
+  expect(sum([-5, -10, 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 float/decimal numbers, returns correct total", () => {
+  expect(sum([1.5, 2.5, 3])).toBe(7);
+});
+test("sums decimal numbers with floating point safely", () => {
+  const result = sum([1.2, 0.6, 0.005]);
+  expect(result).toBeCloseTo(1.805);
+});
 // 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("ignore non-number values and sum only numbers", () => {
+  expect(sum(["hello", 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("array with only non-number values returns 0", () => {
+  expect(sum(["a", "b", {}, [], "hello"])).toBe(0);
+});
+