London | 26-ITP-May | Bisrat Tesfay | Sprint 1 | Coursework/sprint 1

Sprint-1/fix/median.js

@@ -6,9 +6,25 @@
 // 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;
+  } // If list is NOT an array, return null.
+
+  const numbers = list.filter((item) => typeof item === "number");
+  // Keep the item only if its type is number.
+  if (numbers.length === 0) {
+    return null;
+  }
+
+  numbers.sort((a, b) => a - b); // This sorts numbers from smallest to largest
+
+  const middleIndex = Math.floor(numbers.length / 2);
+
+  if (numbers.length % 2 === 0) {
+    return (numbers[middleIndex - 1] + numbers[middleIndex]) / 2;
+  }
+
+  return numbers[middleIndex];
 }
 
 module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,13 @@
-function dedupe() {}
+function dedupe(array) {
+  const newArray = [];
+
+  for (let i = 0; i < array.length; i++) {
+    if (!newArray.includes(array[i])) {
+      newArray.push(array[i]);
+    }
+  }
+
+  return newArray;
+}
+
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -16,13 +16,44 @@ 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");
+
+// Empty array
+test("should return an empty array when given an empty array", () => {
+  const array = [];
+  const result = dedupe(array);
+
+  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
 
+// No duplicates
+test("should return a copy when the array has no duplicates", () => {
+  const array = [1, 2, 3];
+  const result = dedupe(array);
+
+  expect(result).toEqual([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 
+// Then it should return a new array with duplicates removed while preserving the
 // first occurrence of each element from the original array.
+
+// Remove duplicate strings
+test("should remove duplicate strings and keep first occurrence", () => {
+  const array = ["a", "a", "a", "b", "b", "c"];
+  const result = dedupe(array);
+
+  expect(result).toEqual(["a", "b", "c"]);
+});
+
+// Remove duplicate numbers
+test("should remove duplicate numbers and keep first occurrence", () => {
+  const array = [5, 1, 1, 2, 3, 2, 5, 8];
+  const result = dedupe(array);
+
+  expect(result).toEqual([5, 1, 2, 3, 8]);
+});

Sprint-1/implement/max.js

@@ -1,4 +1,19 @@
 function findMax(elements) {
+  let max = -Infinity; // Start with the smallest possible value.
+
+  // loop
+  for (let i = 0; i < elements.length; i++) {
+    if (typeof elements[i] === "number") {
+      // Check if the current element is a number and ignores strings, objects, null
+
+      if (elements[i] > max) {
+        // If it is bigger, update max with this new bigger number
+        max = elements[i];
+      }
+    }
+  }
+  return max;
 }
 
+// Export the function so it can be used in the test file
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -16,28 +16,54 @@ 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", () => {
+  expect(findMax([])).toEqual(-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, returns that number", () => {
+  expect(findMax([5])).toEqual(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("returns the largest number from positive and negative numbers", () => {
+  expect(findMax([-5, 10, -2, 7])).toEqual(10);
+});
+
 // Given an array with just negative numbers
 // When passed to the max function
 // Then it should return the closest one to zero
 
+test("returns the closest number to zero when all numbers are negative", () => {
+  expect(findMax([-10, -3, -20])).toEqual(-3);
+});
+
 // Given an array with decimal numbers
 // When passed to the max function
 // Then it should return the largest decimal number
 
+test("returns the largest decimal number", () => {
+  expect(findMax([1.2, 5.8, 3.4])).toEqual(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("ignores non-number values", () => {
+  expect(findMax(["hey", 10, "hi", 60, 10])).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("returns -Infinity when there are no numbers", () => {
+  expect(findMax(["banana", "orange"])).toEqual(-Infinity);
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,12 @@
 function sum(elements) {
+  let total = 0;
+  for (let i = 0; i < elements.length; i++) {
+    // Only add numbers and ignore other data types
+    if (typeof elements[i] === "number") {
+      total = total + elements[i];
+    }
+  }
+  return total;
 }
 
 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", () => {
+  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 with one number, returns that number", () => {
+  expect(sum([5])).toEqual(5);
+});
+
 // Given an array containing negative numbers
 // When passed to the sum function
 // Then it should still return the correct total sum
 
+test("returns the correct total with negative numbers", () => {
+  expect(sum([-5, 10, -2])).toEqual(3);
+});
+
 // Given an array with decimal/float numbers
 // When passed to the sum function
 // Then it should return the correct total sum
 
+test("returns the correct total with decimal numbers", () => {
+  expect(sum([1.5, 2.5])).toEqual(4);
+});
+
 // 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("ignores non-number values and sums numbers only", () => {
+  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("returns 0 when there are no numbers", () => {
+  expect(sum(["hello", "world"])).toEqual(0);
+});

Sprint-1/refactor/includes.js

@@ -1,12 +1,22 @@
 // Refactor the implementation of includes to use a for...of loop
 
-function includes(list, target) {
+/*function includes(list, target) {
   for (let index = 0; index < list.length; index++) {
     const element = list[index];
     if (element === target) {
       return true;
     }
   }
+  return false;
+} */
+
+function includes(list, target) {
+  for (const element of list) {
+    if (element === target) {
+      return true;
+    }
+  }
+
   return false;
 }