London | 26-ITP-May | Damilola Odumosu | Sprint 1 | Coursework

Sprint-1/fix/median.js

@@ -6,9 +6,28 @@
 // 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;
+  if (!Array.isArray(list)) {
+    return null;
+  }
+  const filteredNumbers = list.filter((num) => Number.isFinite(num));
+
+  if (filteredNumbers.length === 0) {
+    return null;
+  }
+
+  const sortedNumbers = filteredNumbers.sort((a, b) => a - b);
+  let middleIndex;
+  if (sortedNumbers.length % 2 === 0) {
+    middleIndex = sortedNumbers.length / 2;
+    const firstMiddleIndex = sortedNumbers[middleIndex - 1];
+    const secondMiddleIndex = sortedNumbers[middleIndex];
+    return (firstMiddleIndex + secondMiddleIndex) / 2;
+  } else {
+    middleIndex = Math.floor(sortedNumbers.length / 2);
+    return sortedNumbers[middleIndex];
+  }
 }
 
+// console.log(calculateMedian([100, 2, 3, 'f', 4, 9, 9, 0, "hey", 'g']))
+
 module.exports = calculateMedian;

Sprint-1/fix/median.test.js

@@ -1,6 +1,6 @@
 // median.test.js
 
-// Someone has implemented calculateMedian but it isn't
+// Someone has implemented calculateMedian, but it isn't
 // passing all the tests...
 // Fix the implementation of calculateMedian so it passes all tests
 
@@ -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 +1,9 @@
-function dedupe() {}
+function dedupe(elements) {
+  if (elements.length === 0) {
+    return [];
+  }
+
+  return [...new Set(elements)];
+}
+
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -16,13 +16,50 @@ 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, return 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
+const testCaseNoDuplicates = [
+  {
+    input: ["hey", "buddy", "world", "10", "sister", 1],
+    expected: ["hey", "buddy", "world", "10", "sister", 1],
+  },
+  {
+    input: [2, 3, 4, 5, 6, 7],
+    expected: [2, 3, 4, 5, 6, 7],
+  },
+];
+
+testCaseNoDuplicates.forEach(({ input, expected }) => {
+  test("given an array with no duplicates, return a copy of the array", () => {
+    const result = dedupe(input);
+
+    expect(result).toEqual(expected);
+    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.
+const testCaseWithDuplicates = [
+  { input: [1, 2, 2, 3, 1], expected: [1, 2, 3] },
+  { input: ["a", "b", "a", "c", "b"], expected: ["a", "b", "c"] },
+  { input: [5, 5, 1, 1, 2, 3, 2], expected: [5, 1, 2, 3] },
+  {
+    input: ["apple", "banana", "apple", "orange"],
+    expected: ["apple", "banana", "orange"],
+  },
+  { input: [1, "a", 1, "b", "a", 2], expected: [1, "a", "b", 2] },
+  { input: ["hey", "hey", "hey", "hey", "hey", "hey"], expected: ["hey"] },
+];
+testCaseWithDuplicates.forEach(({ input, expected }) => {
+  test("given an array with duplicates, return a new array with only the first occurrence", () => {
+    expect(dedupe(input)).toEqual(expected);
+  });
+});

Sprint-1/implement/max.js

@@ -1,4 +1,22 @@
 function findMax(elements) {
+  if (elements.length === 0) {
+    return -Infinity;
+  }
+  const elementLists = elements.filter((number) => {
+    return typeof number === "number";
+  });
+  if (elementLists.length === 0) {
+    return 0;
+  }
+  if (elementLists.length === 1) {
+    return elementLists[0];
+  }
+  let max = elementLists[0];
+  for (let i = 1; i < elementLists.length; i++) {
+    if (elementLists[i] > max) {
+      max = elementLists[i];
+    }
+  }
+  return max;
 }
-
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -15,29 +15,93 @@ const findMax = require("./max.js");
 // Given an empty array
 // 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", () => {
+  expect(findMax([])).toEqual(-Infinity);
+});
 
 // Given an array with one number
 // When passed to the max function
 // Then it should return that number
+const testCaseArrayWithOneNumber = [
+  { input: [4], expected: 4 },
+  { input: [5], expected: 5 },
+  { input: [10], expected: 10 },
+];
+testCaseArrayWithOneNumber.forEach(({ input, expected }) => {
+  test("given an array with one number, returns that number", () => {
+    expect(findMax(input)).toEqual(expected);
+  });
+});
 
 // Given an array with both positive and negative numbers
 // When passed to the max function
 // Then it should return the largest number overall
+const testCaseArrayWithPositiveAndNegativeNumbers = [
+  { input: [-5, 3, -10, 8, 2, -1], expected: 8 },
+  { input: [-20, 15, -3, 7, -100, 4], expected: 15 },
+  { input: [-1, -50, 0.5, -2, -10], expected: 0.5 },
+];
+testCaseArrayWithPositiveAndNegativeNumbers.forEach(({ input, expected }) => {
+  test("given a mix of positive and negative number, returns the largest number overall", () => {
+    expect(findMax(input)).toEqual(expected);
+  });
+});
 
 // Given an array with just negative numbers
 // When passed to the max function
 // Then it should return the closest one to zero
+const testCaseArrayWithOnlyNegativeNumbers = [
+  { input: [-5, -3, -10, -8, -2, -1], expected: -1 },
+  { input: [-20, -15, -3, -7, -100, -4], expected: -3 },
+  { input: [-1, -50, -0.5, -2, -10], expected: -0.5 },
+];
+
+testCaseArrayWithOnlyNegativeNumbers.forEach(({ input, expected }) => {
+  test("given negative numbers, returns the closest number to zero", () => {
+    expect(findMax(input)).toEqual(expected);
+  });
+});
 
 // Given an array with decimal numbers
 // When passed to the max function
 // Then it should return the largest decimal number
+const testCaseArrayWithOnlyDecimalNumbers = [
+  { input: [1.5, 3.7, 2.4, 8.9, 4.2], expected: 8.9 },
+  { input: [0.2, 0.8, 0.1, 0.6, 0.4], expected: 0.8 },
+  { input: [-1.5, -3.2, -0.7, -5.6, -2.1], expected: -0.7 },
+];
+testCaseArrayWithOnlyDecimalNumbers.forEach(({ input, expected }) => {
+  test("given decimal numbers, returns the largets decimal number", () => {
+    expect(findMax(input)).toEqual(expected);
+  });
+});
 
 // Given an array with non-number values
 // When passed to the max function
 // Then it should return the max and ignore non-numeric values
+const testCaseArrayWithNonNumberValues = [
+  { input: [5, "hello", 10, null, 3], expected: 10 },
+  { input: ["world", -5, 8, undefined, 2], expected: 8 },
+  { input: [true, 4, false, 12, "hey"], expected: 12 },
+  { input: [-10, "hello", -2, null, -20], expected: -2 },
+  { input: [2.5, {}, 7.8, [], "test"], expected: 7.8 },
+];
+testCaseArrayWithNonNumberValues.forEach(({ input, expected }) => {
+  test("given an array including non-numerical values, returns the max and ignore non-numeric values", () => {
+    expect(findMax(input)).toEqual(expected);
+  });
+});
 
 // 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
+const testCaseArrayWithOnlyNonNumberValues = [
+  { input: ["hello", "world", "300"], expected: 0 },
+  { input: [null, undefined, true, false], expected: 0 },
+  { input: [{}, [], "test"], expected: 0 },
+];
+testCaseArrayWithOnlyNonNumberValues.forEach(({ input, expected }) => {
+  test("given an array with only non-number values, returns undefined", () => {
+    expect(findMax(input)).toEqual(expected);
+  });
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,10 @@
 function sum(elements) {
-}
+  const elementsList = elements.filter((element) => Number.isFinite(element));
 
+  let sum = 0;
+  for (let i = 0; i < elementsList.length; i++) {
+    sum += elementsList[i];
+  }
+  return sum;
+}
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -13,24 +13,74 @@ 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 zero", () => {
+  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 of one number, returns number", () => {
+  expect(sum([7])).toEqual(7);
+});
 
 // Given an array containing negative numbers
 // When passed to the sum function
 // Then it should still return the correct total sum
+const testCaseNegativeNumbers = [
+  { input: [-1, -2, -3], expected: -6 },
+  { input: [-5, -10, -15], expected: -30 },
+  { input: [-20, -8, -12], expected: -40 },
+  { input: [-100, -50, -75], expected: -225 },
+];
+testCaseNegativeNumbers.forEach(({ input, expected }) => {
+  test("given an array of negative numbers, returns total sum", () => {
+    expect(sum(input)).toBeCloseTo(expected);
+  });
+});
 
 // Given an array with decimal/float numbers
 // When passed to the sum function
 // Then it should return the correct total sum
-
+const testCaseDecimalNumbers = [
+  { input: [1.5, 2.7, 3.2], expected: 7.4 },
+  { input: [4.25, 6.75, 8.5], expected: 19.5 },
+  { input: [0.5, 1.25, 2.75], expected: 4.5 },
+  { input: [-1.5, -2.25, -3.75], expected: -7.5 },
+];
+testCaseDecimalNumbers.forEach(({ input, expected }) => {
+  test("given an array of decimal numbers, returns total sum", () => {
+    expect(sum(input)).toBeCloseTo(expected);
+  });
+});
 // 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
 
+const testCaseNonNumerical = [
+  { input: [1, "hello", 2, 3], expected: 6 },
+  { input: [5, null, 10, undefined], expected: 15 },
+  { input: ["apple", 4, 6, "banana"], expected: 10 },
+  { input: [2, true, 3, {}, 5], expected: 10 },
+  { input: ["10", 1, 2, 3], expected: 6 },
+];
+testCaseNonNumerical.forEach(({ input, expected }) => {
+  test("given an array of non-numerical values, return sum of numerical values", () => {
+    expect(sum(input)).toEqual(expected);
+  });
+});
 // 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
+const testNonNumberValues = [
+  { input: ["hello", "world"], expected: 0 },
+  { input: [null, undefined, NaN, Infinity, -Infinity], expected: 0 },
+  { input: [true, false, "apple"], expected: 0 },
+  { input: [{}, "10", null], expected: 0 },
+  { input: ["apple", null, undefined, false], expected: 0 },
+];
+testNonNumberValues.forEach(({ input, expected }) => {
+  test("given an array of non number values, return zero", () => {
+    expect(sum(input)).toEqual(expected);
+  });
+});