Sheffield | 26-ITP-Jan | Mahammad Osman | Sprint 1 | Sprint-1

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) || list.length === 0) {
+    return null;
+  }
+
+  const numbers = list.filter((item) => Number.isFinite(item));
+
+  if (numbers.length === 0) {
+    return null;
+  }
+
+  numbers.sort((a, b) => a - b);
+
+  const middleIndex = Math.floor(numbers.length / 2);
+
+  if (numbers.length % 2 !== 0) {
+    return numbers[middleIndex];
+  } else {
+    const leftMiddle = numbers[middleIndex - 1];
+    const rightMiddle = numbers[middleIndex];
+
+    return (leftMiddle + rightMiddle) / 2;
+  }
 }
 
 module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

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

Sprint-1/implement/dedupe.test.js

@@ -11,18 +11,35 @@ E.g. dedupe([5, 1, 1, 2, 3, 2, 5, 8]) returns [5, 1, 2, 3, 8]
 E.g. dedupe([1, 2, 1]) returns [1, 2]
 */
 
-// Acceptance Criteria:
+describe("dedupe", () => {
+  // Acceptance Criteria:
 
-// 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");
+  // Given an empty array
+  // When passed to the dedupe function
+  // Then it should return an empty array
+  test("should return an empty array when passed 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
+  // Given an array with no duplicates
+  // When passed to the dedupe function
+  // Then it should return a copy of the original array
+  test("should return a copy of the original array when there are no duplicates", () => {
+    const input = [1, 2, 3];
 
-// 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.
+    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
+  // first occurrence of each element from the original array.
+  test("should return a new array with duplicates removed while preserving the first occurrence of each element", () => {
+    expect(dedupe(["a", "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 +1,13 @@
 function findMax(elements) {
+  const numbersOnly = elements.filter(
+    (element) => typeof element === "number" && !isNaN(element)
+  );
+
+  if (numbersOnly.length === 0) {
+    return -Infinity;
+  }
+
+  return Math.max(...numbersOnly);
 }
 
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -12,32 +12,56 @@ We have set things up already so that this file can see your function from the o
 
 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");
-
-// Given an array with one number
-// When passed to the max function
-// Then it should return that number
-
-// Given an array with both positive and negative numbers
-// When passed to the max function
-// Then it should return the largest number overall
-
-// Given an array with just negative numbers
-// When passed to the max function
-// Then it should return the closest one to zero
-
-// Given an array with decimal numbers
-// When passed to the max function
-// Then it should return the largest decimal number
-
-// Given an array with non-number values
-// When passed to the max function
-// Then it should return the max and ignore non-numeric values
-
-// 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
+describe("findMax", () => {
+  // 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("should return -Infinity when passed an empty array", () => {
+    expect(findMax([])).toEqual(-Infinity);
+  });
+
+  // Given an array with one number
+  // When passed to the max function
+  // Then it should return that number
+  test("should return the only number when passed an array with one number", () => {
+    expect(findMax([42])).toEqual(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("should return the largest number overall when passed an array with both positive and negative numbers", () => {
+    expect(findMax([-10, 0, 5, -20, 15])).toEqual(15);
+  });
+
+  // Given an array with just negative numbers
+  // When passed to the max function
+  // Then it should return the closest one to zero
+  test("should return the closest number to zero when passed an array with just negative numbers", () => {
+    expect(findMax([-10, -5, -20, -1])).toEqual(-1);
+  });
+
+  // Given an array with decimal numbers
+  // When passed to the max function
+  // Then it should return the largest decimal number
+  test("should return the largest decimal number when passed an array with decimal numbers", () => {
+    expect(findMax([1.5, 2.3, 0.8, 3.1])).toEqual(3.1);
+  });
+
+  // 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("should return the max and ignore non-numeric values when passed an array with non-number values", () => {
+    expect(findMax(["hey", 10, "hi", 60, 10, "300"])).toEqual(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("should return -Infinity when passed an array with ONLY non-number values", () => {
+    expect(findMax(["hey", "hi", "hello"])).toEqual(-Infinity);
+  });
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,12 @@
 function sum(elements) {
+  const numbersOnly = elements.filter(
+    (element) => typeof element === "number" && !isNaN(element)
+  );
+
+  if (numbersOnly.length === 0) {
+    return 0;
+  }
+  return numbersOnly.reduce((acc, curr) => acc + curr, 0);
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -13,24 +13,41 @@ 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("should return 0 when passed an empty array", () => {
+  expect(sum([])).toEqual(0);
+});
 
 // Given an array with just one number
 // When passed to the sum function
 // Then it should return that number
+test("should return the only number when passed an array with one number", () => {
+  expect(sum([42])).toEqual(42);
+});
 
 // Given an array containing negative numbers
 // When passed to the sum function
 // Then it should still return the correct total sum
+test("should return the correct total sum when passed an array containing negative numbers", () => {
+  expect(sum([-10, 20, -5])).toEqual(5);
+});
 
 // Given an array with decimal/float numbers
 // When passed to the sum function
 // Then it should return the correct total sum
+test("should return the correct total sum when passed an array with decimal/float numbers", () => {
+  expect(sum([1.5, 2.3, 0.8, 3.1])).toBeCloseTo(7.7);
+});
 
 // 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("should ignore non-numerical values and return the sum of the numerical elements", () => {
+  expect(sum(["hey", 10, "hi", 60, 10])).toEqual(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("should return 0 when passed an array with ONLY non-number values", () => {
+  expect(sum(["hey", "hi", "hello"])).toEqual(0);
+});