Manchester | 26-ITP-May | Monsur Abdulrahman | Sprint 1 | Module-data-groups

Sprint-1/fix/median.js

@@ -6,9 +6,26 @@
 // 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;
+  // Filtering out non-numeric values
+  const numbers = list.filter(val => typeof val === 'number' && !isNaN(val));
+
+  // Returning null if no numbers are found
+  if (numbers.length === 0) {
+    return null;
+  }
+
+  // Sorting the numbers in ascending order
+  numbers.sort((a, b) => a - b);
+
+  // Calculating the median
+  const middleIndex = Math.floor(numbers.length / 2);
+  if (numbers.length % 2 === 0) {
+    // Even number of elements - average the two middle values
+    return (numbers[middleIndex - 1] + numbers[middleIndex]) / 2;
+  } else {
+    // Odd number of elements - return the middle value
+    return numbers[middleIndex];
+  } 
 }
 
 module.exports = calculateMedian;

Sprint-1/fix/median.test.js

@@ -7,44 +7,28 @@
 const calculateMedian = require("./median.js");
 
 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 },
-  ].forEach(({ input, expected }) =>
-    it(`returns the median for [${input}]`, () => expect(calculateMedian(input)).toEqual(expected))
-  );
-
-  [
-    { input: [3, 1, 2], expected: 2 },
-    { input: [5, 1, 3, 4, 2], expected: 3 },
-    { input: [4, 2, 1, 3], expected: 2.5 },
-    { input: [6, 1, 5, 3, 2, 4], expected: 3.5 },
-    { input: [110, 20, 0], expected: 20 },
-    { input: [6, -2, 2, 12, 14], expected: 6 },
-  ].forEach(({ input, expected }) =>
-    it(`returns the correct median for unsorted array [${input}]`, () => expect(calculateMedian(input)).toEqual(expected))
-  );
-
-  it("doesn't modify the input array [3, 1, 2]", () => {
-    const list = [3, 1, 2];
-    calculateMedian(list);
-    expect(list).toEqual([3, 1, 2]);
+  test("returns the median of a list of numbers", () => {
+    expect(calculateMedian([1, 2, 3])).toBe(2);
+    expect(calculateMedian([1, 2, 3, 4])).toBe(2.5);
+    expect(calculateMedian([1, 2, 3, 4, 5])).toBe(3);
+    expect(calculateMedian([1, 2, 3, 4, 5, 6])).toBe(3.5);
+    expect(calculateMedian([1, 2, 3, 4, 5, 6, 7])).toBe(4);
+    expect(calculateMedian([1, 2, 3, 4, 5, 6, 7, 8])).toBe(4.5);
+    expect(calculateMedian([1])).toBe(1);
+    expect(calculateMedian([])).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))
-  );
+  test("returns null if the list doesn't have numbers", () => {
+    expect(calculateMedian(["a", "b", "c"])).toBe(null);
+    expect(calculateMedian([true, false])).toBe(null);
+    expect(calculateMedian([null, undefined])).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 },
-  ].forEach(({ input, expected }) =>
-    it(`filters out non-numeric values and calculates the median for [${input}]`, () => expect(calculateMedian(input)).toEqual(expected))
-  );
-});
+  test("sorts only numbers in a mixed list and returns the median", () => {
+    expect(calculateMedian([1, "a", 2, "b", 3])).toBe(2);
+    expect(calculateMedian([1, 2, "a", 3, "b", 4])).toBe(2.5);
+    expect(calculateMedian([1, "a", 2, "b", 3, "c"])).toBe(2);
+    expect(calculateMedian([1, 2, 3, "a", "b", "c"])).toBe(2);
+    expect(calculateMedian([1, 2, 3, 4, "a", "b", "c"])).toBe(2.5);
+  });
+}); 

Sprint-1/implement/dedupe.js

@@ -1 +1,5 @@
-function dedupe() {}
+function dedupe(arr) {
+return Array.from(new Set(arr));    
+}
+
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -16,13 +16,24 @@ 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("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 duplicates, it returns a copy of the original array", () => {
+  expect(dedupe([1, 2, 3])).toEqual([1, 2, 3]);
+  expect(dedupe(["a", "b", "c"])).toEqual(["a", "b", "c"]);
+});
 
 // 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 
 // first occurrence of each element from the original array.
+test("given an array of strings or numbers, it returns a new array with duplicates removed while preserving the first occurrence of each element from the original array", () => {
+  expect(dedupe(["a", "a", "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 +1,14 @@
 function findMax(elements) {
+    // Filtering out non-numeric values    
+    const numericElements = elements.filter(element => typeof element === 'number' && !isNaN(element));
+
+    // If there are no numeric values, return -Infinity
+    if (numericElements.length === 0) {
+        return -Infinity;
+    }
+
+    // Using Math.max to find the maximum value in the numeric elements
+    return Math.max(...numericElements);    
 }
 
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -16,28 +16,46 @@ 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, when passed to the max function, then it should return -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, when passed to the max function, then it should return that number", () => {
+  expect(findMax([5])).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 ("Given an array with both positive and negative numbers, when passed to the max function, then it should return the largest number overall", () => {
+  expect(findMax([-10, 20, -30, 40, -50])).toBe(40);
+});
 
 // 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, when passed to the max function, then it should return the closest one to zero", () => {
+  expect(findMax([-10, -20, -30, -40, -50])).toBe(-10);
+});
 // 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, when passed to the max function, then it should return the largest decimal number", () => {
+  expect(findMax([1.5, 2.5, 3.5, 4.5, 5.5])).toBe(5.5);
+});
 
 // 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, when passed to the max function, then it should return the max and ignore non-numeric values", () => {
+  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 ("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", () => {
+  expect(findMax(['hello', 'world'])).toBe(-Infinity);
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,14 @@
 function sum(elements) {
+    // Filtering out non-numeric values
+    const numericElements = elements.filter(element => typeof element === 'number' && !isNaN(element));
+
+    // If there are no numeric values, return 0
+    if (numericElements.length === 0) {
+        return 0;
+    }
+
+    // Using reduce to calculate the sum of the numeric elements
+    return numericElements.reduce((accumulator, currentValue) => accumulator + currentValue, 0);
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -13,24 +13,39 @@ 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 an array with just one number, returns that number", () => {
+  expect(sum([5])).toBe(5);
+});
 // 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 the correct total sum", () => {
+  expect(sum([-10, -20, -30])).toBe(-60);
+});
 
 // 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 the correct total sum", () => {
+  expect(sum([1.5, 2.5, 3.5])).toBe(7.5);
+});     
 // 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 the non-numerical values and returns 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, returns the least surprising value given how it behaves for all other inputs", () => {
+  expect(sum(['hello', 'world'])).toBe(0);
+});

Sprint-1/refactor/includes.js

@@ -1,12 +1,11 @@
 // Refactor the implementation of includes to use a for...of loop
 
 function includes(list, target) {
-  for (let index = 0; index < list.length; index++) {
-    const element = list[index];
-    if (element === target) {
+  for (const item of list) {
+    if (item === target) {
       return true;
     }
-  }
+  }   
   return false;
 }