Sheffield | 26-Jan-ITP | Martha Ogunbiyi| Sprint 1 | Coursework/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;
+  // Step 1: must be an array
+  if (!Array.isArray(list)) return null;
+
+  // Step 2: filter numeric values
+  const numericValues = list.filter(
+    (item) => typeof item === "number" && !Number.isNaN(item)
+  );
+
+  // Step 3: must have at least one number
+  if (numericValues.length === 0) return null;
+
+  // Step 4: sort safely
+  const sortedList = numericValues.slice().sort((a, b) => a - b);
+
+  const middleIndex = Math.floor(sortedList.length / 2);
+
+  // Step 5: median
+  if (sortedList.length % 2 !== 0) {
+    return sortedList[middleIndex];
+  }
+
+  return (sortedList[middleIndex - 1] + sortedList[middleIndex]) / 2;
 }
 
 module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,5 @@
-function dedupe() {}
+function dedupe(elements) {
+  if (elements.length === 0) return [];
+  return elements.filter((item, index) => elements.indexOf(item) === index);
+}
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -16,12 +16,31 @@ 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", () => {
+    const input = [];
+    const result = dedupe(input);
+    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 returns return a copy of the original array", () => {
+  const input = [1, 2, 3, 4, 5];
+  const result = dedupe(input);
+  expect(result).toEqual([1, 2, 3, 4, 5]);
+});
 
 // 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
+// Then it should remove the duplicate values, preserving the first occurrence of each element
+test("given an array with strings, it removes the duplicate, preserving first occurrence of each element", () => {
+  const input = ["a", "a", "a", "b", "b", "c"];
+  const result = dedupe(input);
+  expect(result).toEqual(["a", "b", "c"]);
+});
+test("given an array with numbers it removes the duplicate, preserving first occurrence of each element", () => {
+  const input = [5, 1, 1, 2, 3, 2, 5, 8];
+  const result = dedupe(input);
+  expect(result).toEqual([5, 1, 2, 3, 8]);
+});

Sprint-1/implement/max.js

@@ -1,4 +1,10 @@
 function findMax(elements) {
+  if (!Array.isArray(elements) || elements.length === 0) return -Infinity;
+  return Math.max(
+    ...elements.filter(
+      (item) => typeof item === "number" && !Number.isNaN(item)
+    )
+  );
 }
 
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -16,28 +16,62 @@ 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", () => {
+    const input = []
+    const result = findMax(input)
+    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, its should return that number', () => {
+    const input = [5]
+    const result = findMax(input)
+    expect(result).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, it should return largest overall', () => {
+    const input = [5, -5, -10, -1, 6, 8, 10]
+    const result = findMax(input)
+    expect(result).toBe(10);
+});
 
 // 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, it should return the closest one to zero', () => {
+    const input = [-10, -5, -2, -8];
+    const result = findMax(input);
+    expect(result).toBe(-2);
+})
 
 // 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 just decimal numbers, it should return the largest decimal number", () => {
+  const input = [1.0, 2.5, 2.2, 5.8];
+  const result = findMax(input);
+  expect(result).toBe(5.8);
+});
 
 // 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 value, it should return the max and ignore non-numeric value", () => {
+  const input = [4, 5, 'arr', 2, []," ", 15, 8];
+  const result = findMax(input);
+  expect(result).toBe(15);
+});
 
 // 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 value, it should return the least surprising value given how it behaves for all other inputs", () => {
+  const input = [true, {}, "arr", null, [], " ", NaN];
+  const result = findMax(input);
+  expect(result).toBe(-Infinity);
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,8 @@
 function sum(elements) {
+    if (!Array.isArray(elements) || elements.length === 0) return 0;
+    return elements
+      .filter((item) => typeof item === "number" && !Number.isNaN(item))
+      .reduce((acc, n) => acc + n, 0);
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -13,24 +13,53 @@ 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", () => {
+  const input = [];
+  const result = sum(input);
+  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", () => {
+  const input = [5];
+  const result = sum(input);
+  expect(result).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, it should return the correct total sum", () => {
+  const input = [5, -6, 10, -12];
+  const result = sum(input);
+  expect(result).toBe(-3);
+});
 
 // 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", () => {
+  const input = [5, 6.6, 10, 5.12];
+  const result = sum(input);
+  expect(result).toBe(26.720000000000002);
+});
 
 // 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, it should ignore the numerical values and return sum of numeric element", () => {
+  const input = [4, 5, "arr", 2, [], " ", 15, 8];
+  const result = sum(input);
+  expect(result).toBe(34);
+});
 
 // 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, it should return least surprising value given how it behaves for all other inputs", () => {
+  const input = [true, {}, "arr", null, [], " ", NaN];
+  const result = sum(input);
+  expect(result).toBe(0);
+});

Sprint-1/refactor/includes.js

@@ -1,8 +1,7 @@
 // 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];
+  for (const element of list) {
     if (element === target) {
       return true;
     }
@@ -11,3 +10,10 @@ function includes(list, target) {
 }
 
 module.exports = includes;
+
+// const array = ["a", "b", "c"];
+
+// for (const element of array) {
+//   console.log(element);
+// } for (variable of iterable) statement
+