Sheffield | 26-ITP-Jan | Mona -Eltantawy | Sprint 1 | Data- Groups/sprint 1

Sprint-1/fix/median.js

@@ -6,9 +6,29 @@
 // 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;
+  // Check if input is an array
+  if (!Array.isArray(list)) return null;
+
+  // Filter only valid numbers
+  const numbers = list.filter(
+    (item) => typeof item === "number" && Number.isFinite(item)
+  );
+
+  // If no valid numbers, return null
+  if (numbers.length === 0) return null;
+
+  // Sort without mutating original array
+  const sorted = [...numbers].sort((a, b) => a - b);
+
+  const middle = Math.floor(sorted.length / 2);
+
+  // Even length
+  if (sorted.length % 2 === 0) {
+    return (sorted[middle - 1] + sorted[middle]) / 2;
+  }
+
+  // Odd length
+  return sorted[middle];
 }
 
 module.exports = calculateMedian;

Sprint-1/fix/median.test.js

@@ -13,7 +13,8 @@ describe("calculateMedian", () => {
     { input: [1, 2, 3, 4], expected: 2.5 },
     { input: [1, 2, 3, 4, 5, 6], expected: 3.5 },
   ].forEach(({ input, expected }) =>
-    it(`returns the median for [${input}]`, () => expect(calculateMedian(input)).toEqual(expected))
+    it(`returns the median for [${input}]`, () =>
+      expect(calculateMedian(input)).toEqual(expected))
   );
 
   [
@@ -24,7 +25,8 @@ describe("calculateMedian", () => {
     { input: [110, 20, 0], expected: 20 },
     { input: [6, -2, 2, 12, 14], expected: 6 },
   ].forEach(({ input, expected }) =>
-    it(`returns the correct median for unsorted array [${input}]`, () => expect(calculateMedian(input)).toEqual(expected))
+    it(`returns the correct median for unsorted array [${input}]`, () =>
+      expect(calculateMedian(input)).toEqual(expected))
   );
 
   it("doesn't modify the input array [3, 1, 2]", () => {
@@ -33,8 +35,17 @@ describe("calculateMedian", () => {
     expect(list).toEqual([3, 1, 2]);
   });
 
-  [ 'not an array', 123, null, undefined, {}, [], ["apple", null, undefined] ].forEach(val =>
-    it(`returns null for non-numeric array (${val})`, () => expect(calculateMedian(val)).toBe(null))
+  [
+    "not an array",
+    123,
+    null,
+    undefined,
+    {},
+    [],
+    ["apple", null, undefined],
+  ].forEach((val) =>
+    it(`returns null for non-numeric array (${val})`, () =>
+      expect(calculateMedian(val)).toBe(null))
   );
 
   [
@@ -45,6 +56,7 @@ describe("calculateMedian", () => {
     { input: [3, "apple", 1, null, 2, undefined, 4], expected: 2.5 },
     { input: ["banana", 5, 3, "apple", 1, 4, 2], expected: 3 },
   ].forEach(({ input, expected }) =>
-    it(`filters out non-numeric values and calculates the median for [${input}]`, () => expect(calculateMedian(input)).toEqual(expected))
+    it(`filters out non-numeric values and calculates the median for [${input}]`, () =>
+      expect(calculateMedian(input)).toEqual(expected))
   );
 });

Sprint-1/implement/dedupe.js

@@ -1 +1,5 @@
-function dedupe() {}
+function dedupe(arr) {
+  const set = new Set(arr);
+  return [...set];
+}
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -16,13 +16,31 @@ E.g. dedupe([1, 2, 1]) returns [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");
+describe("dedupe", () => {
+  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 duplication, it returns a copy of the array", () => {
+  const input = [1, 2, 3];
+  const result = dedupe(input);
+
+  expect(result).toEqual([1, 2, 3]);
+  expect(result).not.toBe(input);
+});
 // Given an array of strings or numbers
 // When passed to the dedupe function
-// Then it should return a new array with duplicates removed while preserving the 
+// Then it should return a new array with duplicates removed while preserving the
 // first occurrence of each element from the original array.
+test("removes duplicates and preserves first occurrence", () => {
+  expect(dedupe(["a", "a", "a", "b", "b", "b", "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]);
+});

Sprint-1/implement/max.js

@@ -1,4 +1,7 @@
-function findMax(elements) {
+function findMax(arr) {
+  return arr
+    .filter((item) => typeof item === "number")
+    .reduce((acc, num) => (num > acc ? num : acc), -Infinity);
 }
 
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -16,28 +16,47 @@ 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");
-
+describe("max function", () => {
+  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("array with both positive and negative numbers, returns the largest", () => {
+  expect(findMax([-10, 0, 5, 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("array with only 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("array with decimal numbers, returns the largest decimal", () => {
+  expect(findMax([1.5, 2.7, 0.3])).toBe(2.7);
+});
 
 // 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("array with non-number values, ignores non-numeric and returns max 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("array with only non-number values, returns -Infinity", () => {
+  expect(findMax(["a", "b", null, {}])).toBe(-Infinity);
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,7 @@
-function sum(elements) {
+function sum(arr) {
+  return arr
+    .filter((item) => typeof item === "number")
+    .reduce((acc, num) => acc + num, 0);
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -13,24 +13,40 @@ 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")
-
+describe("sum function", () => {
+  test("given an empty array, returns 0", () => {
+    expect(sum([])).toEqual(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 the same number", () => {
+  expect(sum([1])).toEqual(1);
+});
 
 // 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 with negative numbers, returns the correct total", () => {
+  expect(sum([1, 2, 3, -2])).toEqual(4);
+});
 
 // 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 number, returns the correct total sum", () => {
+  expect(sum([1, 2, 3, 1.5, 2.1])).toEqual(9.6);
+});
 // 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 , returns the sum of the numerical elements", () => {
+  expect(sum([1, "h", 3, "sss", 5])).toEqual(9);
+});
 // 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(["m", "h", "sss", "hhh"])).toEqual(0);
+});