London | May-2025 | Ikenna Agulobi | Data Groups | sprint-1

Sprint-1/fix/median.js

@@ -6,9 +6,30 @@
 // 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;
+  //Checking the input provided to ensure it's an Array
+  if (!Array.isArray(list)) {
+    return null;
+  }
+  //Filtering out numbers from the array without changing the original array. Creates new array filteredNumbersOnly!
+  const filteredNumbersOnly = list.filter(
+    (element) => typeof element === "number" && !isNaN(element)
+  );
+  //if  the array has no valid numbers, it returns null
+  if (filteredNumbersOnly.length === 0) {
+    return null;
+  }
+  //Sorting numbers in the array from the ascending order. Spread operator creates new array to avoid changing the original one.
+  const sortedList = [...filteredNumbersOnly].sort((a, b) => a - b);
+  //If the array length is odd, return the middle number
+  if (sortedList.length % 2 === 1) {
+    const middleIndex = Math.floor(sortedList.length / 2);
+    return sortedList[middleIndex];
+  } else {
+    // If the array length is even, return the average of the two middle numbers.
+    const midddleNum1 = sortedList[sortedList.length / 2 - 1];
+    const midddleNum2 = sortedList[sortedList.length / 2];
+    return (midddleNum1 + midddleNum2) / 2;
+  }
 }
 
 module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,7 @@
-function dedupe() {}
+function dedupe(arr) {
+  const newArray = [... new Set(arr)]
+  return newArray;
+};
+
+// console.log(dedupe(["b", "c", "a", "b", "c", 1, "a", 2]));
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -16,12 +16,27 @@ 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", () => {
+  let emptyArr = []
+  let result = dedupe(emptyArr);
+  expect(result).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 should return a copy of the original array", () => {
+  let arrayWithNoDuplicates = [1, 2, 3];
+  let result = dedupe(arrayWithNoDuplicates);
+  expect(result).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
+test("Given an array with strings or numbers", () => {
+  let arrayNumsOrStrings = ["b", "c", "a", "b", "c", 1, "a", 2];
+  let result = dedupe(arrayNumsOrStrings);
+  expect(result).toEqual(["b", "c", "a", 1, 2]);
+});

Sprint-1/implement/max.js

@@ -1,4 +1,21 @@
 function findMax(elements) {
+  let numbers = [];
+  // using for loop to extract numbers from the Array incase array is mixed
+  for (let i = 0; i < elements.length; i++) {
+    if (typeof elements[i] === "number") {
+      numbers.push(elements[i]);
+    }
+  }
+  // Return the largest number, else -Infinity if no numbers are found
+  if (numbers.length > 0) {
+    return Math.max(...numbers);
+  } else {
+    return -Infinity;
+  }
 }
 
+// console.log(findMax([1, 2, 3, 4, 10]));
+// console.log(findMax([]));
+// console.log(findMax([1]));
+// console.log(findMax( [4, "hello", "fruit", 2, 5]))
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -16,28 +16,60 @@ 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",() => {
+  let emptyArray = []
+  let result = findMax(emptyArray);
+  expect(result).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, return that number", () => {
+  let oneNumArray = [12];
+  let result = findMax(oneNumArray);
+  expect(result).toEqual(12);
+});
 
 // 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, it should return the largest number overall", () => {
+  let positiveAndNegativeNum= [-2, 3, 4,-5];
+  let result = findMax(positiveAndNegativeNum);
+  expect(result).toEqual(4);
+});
 
 // 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, return the closest one to zero", () => {
+  let negativeNumArray = [-1, -2, -3];
+  let result = findMax(negativeNumArray);
+  expect(result).toEqual(-1);
+});
 
 // 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, return the largest decimal number", () => {
+  let decimalNumArray = [1.5, 2.5, 2.2];
+  let result = findMax(decimalNumArray);
+  expect(result).toEqual(2.5);
+});
 
 // 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("Given an array with non-number values, Then it should return the max and ignore non-numeric values", () => {
+  let mixedArray = [4, "hello", "fruit", 2, 5];
+  let result = findMax(mixedArray);
+  expect(result).toEqual(5);
+});
 
 // 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, return the least surprising value given how it behaves for all other inputs", () => {
+  expect(findMax(["apple", null, undefined, {}, []])).toEqual(-Infinity);
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,21 @@
 function sum(elements) {
+  let onlyNumbers = [];
+  //Extract numbers from the Array incase array is mixed
+  for (let i = 0; i < elements.length; i++) {
+    if (typeof elements[i] === "number") {
+      onlyNumbers.push(elements[i]);
+    }
+  }
+  if (onlyNumbers.length > 0) {
+    return onlyNumbers.reduce((a, b) => a + b);
+  } else {
+    return 0;
+  }
 }
 
+console.log(sum([10, 20, 30]));
+console.log(sum(["hey", 10, "hi", 60, 10]));
+console.log(sum([]));
+
+
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -13,24 +13,46 @@ 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 = [];
+  let result = sum(emptyArray)
+  expect(result).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, it should return that number", () => {
+  let oneNumArray = [23];
+  let result = sum(oneNumArray);
+  expect(result).toBe(23);
+});
 
 // 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, it should still return the correct total sum", () => {
+  expect(sum([-2, -4, -1])).toBe(-7);
+});
 
 // 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, it should return the correct total sum", () => {
+  expect(sum([2.5, 4.5, 1.1])).toBe(8.1);
+});
+
 // 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, return the sum of the numerical elements", () => {
+  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, should return 0", () => {
+  expect(sum(["apple", null, undefined, {}, []])).toBe(0);
+});