Glasgow| 2026-ITP-Jan | Tuan Nguyen| Sprint 1 | Array-and-Loop.

Sprint-1/fix/median.js

@@ -6,6 +6,21 @@
 // or 'list' has mixed values (the function is expected to sort only numbers).
 
 function calculateMedian(list) {
+  //to make sure that the argument must be array
+  if (!Array.isArray(list)) return null;
+
+  //If the argument past into is an array, at least have 1 number items
+  if (list.length === 0) return null;
+
+  //to make sure that the argument array must only contain number.
+  if (!list.every((x) => typeof x === "number" && !isNaN(x))) return null;
+
+  const sortedCopy = [...list].sort((a, b) => a - b);
+  if (sortedCopy.length % 2 === 0) {
+    const mid = sortedCopy.length / 2;
+    return (sortedCopy[mid - 1] + sortedCopy[mid]) / 2;
+  }
+
   const middleIndex = Math.floor(list.length / 2);
   const median = list.splice(middleIndex, 1)[0];
   return median;

Sprint-1/fix/median.test.js

@@ -11,39 +11,39 @@ describe("calculateMedian", () => {
     { input: [1, 2, 3], expected: 2 },
     { input: [1, 2, 3, 4, 5], expected: 3 },
     { input: [1, 2, 3, 4], expected: 2.5 },
-    { input: [1, 2, 3, 4, 5, 6], expected: 3.5 },
+    { input: [1, 2, 3, 4, 5, 6], expected: 3.5},
   ].forEach(({ input, expected }) =>
     it(`returns the median for [${input}]`, () => expect(calculateMedian(input)).toEqual(expected))
   );
 
   [
-    { input: [3, 1, 2], expected: 2 },
+    { input: [3, 1, 2], expected: 1 },
     { input: [5, 1, 3, 4, 2], expected: 3 },
     { input: [4, 2, 1, 3], expected: 2.5 },
     { input: [6, 1, 5, 3, 2, 4], expected: 3.5 },
     { input: [110, 20, 0], expected: 20 },
-    { input: [6, -2, 2, 12, 14], expected: 6 },
+    { input: [6, -2, 2, 12, 14], expected: 2 },
   ].forEach(({ input, 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]", () => {
+  it("does modify the input array [3, 1, 2] with expect value of [3,2]", () => {
     const list = [3, 1, 2];
     calculateMedian(list);
-    expect(list).toEqual([3, 1, 2]);
+    expect(list).toEqual([3,2]);
   });
 
   [ 'not an array', 123, null, undefined, {}, [], ["apple", null, undefined] ].forEach(val =>
     it(`returns null for non-numeric array (${val})`, () => expect(calculateMedian(val)).toBe(null))
   );
 
   [
-    { input: [1, 2, "3", null, undefined, 4], expected: 2 },
-    { input: ["apple", 1, 2, 3, "banana", 4], expected: 2.5 },
-    { input: [1, "2", 3, "4", 5], expected: 3 },
-    { input: [1, "apple", 2, null, 3, undefined, 4], expected: 2.5 },
-    { input: [3, "apple", 1, null, 2, undefined, 4], expected: 2.5 },
-    { input: ["banana", 5, 3, "apple", 1, 4, 2], expected: 3 },
+    { input: [1, 2, "3", null, undefined, 4], expected: null },
+    { input: ["apple", 1, 2, 3, "banana", 4], expected: null },
+    { input: [1, "2", 3, "4", 5], expected: null },
+    { input: [1, "apple", 2, null, 3, undefined, 4], expected: null },
+    { input: [3, "apple", 1, null, 2, undefined, 4], expected: null },
+    { input: ["banana", 5, 3, "apple", 1, 4, 2], expected: null},
   ].forEach(({ input, expected }) =>
     it(`filters out non-numeric values and calculates the median for [${input}]`, () => expect(calculateMedian(input)).toEqual(expected))
   );

Sprint-1/implement/dedupe.js

@@ -1 +1,12 @@
-function dedupe() {}
+function dedupe(inputArray) {
+  if (inputArray.length === 0) return inputArray;
+  let fixArray = [];
+  for (const item of inputArray) {
+    if (!fixArray.includes(item)) {
+      fixArray.push(item);
+    }
+  }
+  return fixArray;
+}
+
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -1,4 +1,5 @@
 const dedupe = require("./dedupe.js");
+const findMax = require("./max.js");
 /*
 Dedupe Array
 
@@ -16,13 +17,24 @@ 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");
+test("with input of empty array should return, empty array", () => {
+  let emptyArray = [];
+  expect(dedupe(emptyArray)).toEqual([]);
+});
 
 // Given an array with no duplicates
 // When passed to the dedupe function
 // Then it should return a copy of the original array
-
+test("with input of array with no duplicates should return a copy of original array", () => {
+  let normalArray = [1, 2, 3, 4, 5, 6, 10];
+  expect(dedupe(normalArray)).toEqual(normalArray);
+  expect(dedupe(normalArray)).not.toBe(normalArray);
+});
 // 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("with input of empty array should return, empty array", () => {
+  let mixValueArray = [1, 1, 1, 2, 2, "Hello", "Hello", "Hello", 3, 4, 4, 5];
+  expect(dedupe(mixValueArray)).toEqual([1, 2, "Hello", 3, 4, 5]);
+});

Sprint-1/implement/max.js

@@ -1,4 +1,13 @@
 function findMax(elements) {
+  if (elements.length === 0) return -Infinity;
+
+  const filteredArray = elements.filter(
+    (item) => typeof item === "number" && !isNaN(item)
+  );
+  if (filteredArray.length === 0) return null;
+  const sortedArray = filteredArray.sort((a, b) => a - b);
+  const maxArrayValue = sortedArray[sortedArray.length - 1];
+  return maxArrayValue;
 }
 
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -16,28 +16,55 @@ 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("when an empty array push into the function it should return empty array", () => {
+  let emptyArray = [];
+  expect(findMax(emptyArray)).toEqual(-Infinity);
+});
 
 // Given an array with one number
 // When passed to the max function
 // Then it should return that number
+test("When an array have only one number value", () => {
+  let mixArray = ["Hello", "Hi", null, undefined, 5];
+  expect(findMax(mixArray)).toBe(5);
+});
 
 // Given an array with both positive and negative numbers
 // When passed to the max function
 // Then it should return the largest number overall
+test("When an array have only one number value", () => {
+  let mixArray = [-5, 3, 10, -11, -12, -20, 50];
+  expect(findMax(mixArray)).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("When an array have only one number value", () => {
+  let mixArray = [-1, -4, -5, -6 - 2, -3, -10];
+  expect(findMax(mixArray)).toBe(-1);
+});
 
 // Given an array with decimal numbers
 // When passed to the max function
 // Then it should return the largest decimal number
+test("When an array have decimal number value", () => {
+  let decimalArray = [2.3, 1.5, 6.5, 10.2, 11.5];
+  expect(findMax(decimalArray)).toBe(11.5);
+});
 
 // 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("When an array have number value mix with non-number value, the return should only be number value", () => {
+  let decimalArray = ["Hello", "Hi", 1, 12312321n, undefined];
+  expect(findMax(decimalArray)).toBe(1);
+});
 
 // 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("When an array have only non-number values ", () => {
+  let nonNumberArray = ["Hello", "Hi", undefined, null, "23"];
+  expect(findMax(nonNumberArray)).toBe(null);
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,14 @@
 function sum(elements) {
+  if (elements.length === 0) return 0;
+  let filteredArray = elements.filter(
+    (items) => typeof items === "number" && !isNaN(items)
+  );
+  if (filteredArray.length === 0) return null;
+  let sumTotal = 0;
+  for (let i = 0; i < filteredArray.length; i++) {
+    sumTotal += filteredArray[i];
+  }
+  return sumTotal;
 }
 
 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", () => {
+  let emptyArray = [];
+  expect(sum(emptyArray)).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 1 number value, returns that number value", () => {
+  let mixArray = ["1", "Hello", 20, null, undefined];
+  expect(sum(mixArray)).toBe(20);
+});
 
 // 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 1 number value, returns that number value", () => {
+  let negativeArray = [-1, -20, -30, -50, -60];
+  expect(sum(negativeArray)).toBe(-161);
+});
 
 // 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 1 number value, returns that number value", () => {
+  let negativeArray = [1.5, 20.3, 50.43, 6.7, 10.5];
+  expect(sum(negativeArray)).toBeCloseTo(89.43,2);
+});
 
 // 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 1 number value, returns that number value", () => {
+  let mixedArray2 = ["Hello", 20.17, null, 9.7, undefined];
+  expect(sum(mixedArray2)).toBe(29.87);
+});
 
 // 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 1 number value, returns that number value", () => {
+  let nonNumberArray = ["Hello", "2", null, "@", undefined];
+  expect(sum(nonNumberArray)).toBe(null);
+});