London | Nadarajah_Sripathmanathan | Sprint-2 | Week3

Sprint-1/fix/median.js

@@ -3,9 +3,18 @@
 // If you're in the Sprint-1 directory, you can run `npm test -- fix` to run the tests in the fix directory
 
 function calculateMedian(list) {
-  const middleIndex = Math.floor(list.length / 2);
-  const median = list.splice(middleIndex, 1)[0];
-  return median;
+  if (!list || list.length === 0) {
+    return null;
+  }
+
+  const sortedList = list.slice().sort((a, b) => a - b);
+  const middleIndex = Math.floor(sortedList.length / 2);
+
+  if (sortedList.length % 2 === 0) {
+    return (sortedList[middleIndex - 1] + sortedList[middleIndex]) / 2;
+  } else {
+    return sortedList[middleIndex];
+  }
 }
 
-module.exports = calculateMedian;
+module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,20 @@
-function dedupe() {}
+
+function dedupe(arr) {
+        if (!(arr instanceof Array)) {
+          return [];
+        }
+
+    const seen = new Set();
+    const result = [];
+
+    for (const item of arr) {
+      if (!seen.has(item)) {
+        seen.add(item);
+        result.push(item);
+      }
+    }
+
+    return result;
+  }
+
+  module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -1,4 +1,5 @@
 const dedupe = require("./dedupe.js");
+
 /*
 Dedupe Array
 
@@ -13,15 +14,50 @@ E.g. dedupe([1, 2, 1]) target output: [1, 2]
 
 // 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");
+describe('dedupe', () => {
+  // Given an empty array
+  // When passed to the dedupe function
+  // Then it should return an empty array
+  it("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
+  it("given an array with no duplicates, it returns a copy of the original array", () => {
+    const arr = [1, 2, 3];
+    expect(dedupe(arr)).toEqual(arr);
+  });
+
+  it("given an array of strings with no duplicates, it returns a copy of the original array", () => {
+    const arr = ['a', 'b', 'c'];
+    expect(dedupe(arr)).toEqual(arr);
+  });
+
+  // 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
+  it("given an array with duplicate numbers, it removes the duplicate values, preserving the first occurrence", () => {
+    expect(dedupe([5, 1, 1, 2, 3, 2, 5, 8])).toEqual([5, 1, 2, 3, 8]);
+  });
+
+  it("given an array with duplicate strings, it removes the duplicate values, preserving the first occurrence", () => {
+    expect(dedupe(['a', 'a', 'a', 'b', 'b', 'c'])).toEqual(['a', 'b', 'c']);
+  });
+
+  it("given an array with mixed duplicate types, it removes the duplicate values, preserving the first occurrence", () => {
+    expect(dedupe([1, '1', 1, '2', 2])).toEqual([1, '1', '2', 2]);
+  });
 
-// Given an array with no duplicates
-// When passed to the dedupe function
-// Then it should return a copy of the original array
+  it("given an array with duplicate values in different order, it removes the duplicate values, preserving the first occurrence", () => {
+    expect(dedupe([1, 2, 1])).toEqual([1, 2]);
+  });
 
-// 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
+  it("given an invalid input, it returns an empty array", () => {
+    expect(dedupe(null)).toEqual([]);
+    expect(dedupe(undefined)).toEqual([]);
+    expect(dedupe({})).toEqual([]);
+    expect(dedupe("string")).toEqual([]);
+  });
+});

Sprint-1/implement/max.js

@@ -1,4 +1,15 @@
 function findMax(elements) {
-}
-
-module.exports = findMax;
+    if (!elements || elements.length === 0) {
+      return -Infinity;
+    }
+
+    let max = -Infinity;
+    for (let i = 0; i < elements.length; i++) {
+      if (typeof elements[i] === 'number' && elements[i] > max) {
+        max = elements[i];
+      }
+    }
+    return max;
+  }
+
+  module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -15,29 +15,48 @@ 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([])).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, returns 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, returns the largest number", () => {
+  expect(findMax([-10, 5, 20, -5])).toBe(20);
+});
 
 // 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, returns the closest one to zero", () => {
+  expect(findMax([-10, -5, -20, -1])).toBe(-1);
+});
 
 // 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, returns the largest decimal number", () => {
+  expect(findMax([1.5, 2.7, 1.1, 3.9])).toBe(3.9);
+});
 
 // 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, returns the max and ignores 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, returns -Infinity", () => {
+    expect(findMax(["a","b","c"])).toBe(-Infinity);
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,14 @@
 function sum(elements) {
-}
-
-module.exports = sum;
+    if (!Array.isArray(elements)) {
+      return 0; // Handle cases where input is not an array
+    }
+    let total = 0;
+    for (let i = 0; i < elements.length; i++) {
+      if (typeof elements[i] === 'number') {
+        total += elements[i];
+      }
+    }
+    return total;
+  }
+
+  module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -1,36 +1,57 @@
-/* Sum the numbers in an array
-
-In this kata, you will need to implement a function that sums the numerical elements of an array
-
-E.g. sum([10, 20, 30]), target output: 60
-E.g. sum(['hey', 10, 'hi', 60, 10]), target output: 80 (ignore any non-numerical elements)
-*/
-
 const sum = require("./sum.js");
 
 // Acceptance Criteria:
 
 // 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 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 with negative numbers, returns correct total", () => {
+  expect(sum([-1, -2, 3])).toBe(0);
+});
 
 // 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 numbers, returns correct total", () => {
+  expect(sum([1.5, 2.5, 3])).toBe(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("given an array with mixed values, ignores non-numbers", () => {
+  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 0", () => {
+    expect(sum(['a','b','c'])).toBe(0);
+});
+
+test("given a null input, returns 0", () => {
+  expect(sum(null)).toBe(0);
+});
+
+test("given an undefined input, returns 0", () => {
+  expect(sum(undefined)).toBe(0);
+});
+
+test("given an object input, returns 0", () => {
+  expect(sum({})).toBe(0);
+});

Sprint-1/refactor/includes.js

@@ -1,4 +1,4 @@
-// Refactor the implementation of includes to use a for...of loop
+/*// Refactor the implementation of includes to use a for...of loop
 
 function includes(list, target) {
   for (let index = 0; index < list.length; index++) {
@@ -11,3 +11,14 @@ function includes(list, target) {
 }
 
 module.exports = includes;
+*/
+function includes(list, target) {
+  for (const element of list) {
+    if (element === target) {
+      return true;
+    }
+  }
+  return false;
+}
+
+module.exports = includes;

Sprint-2/debug/address.js

@@ -1,5 +1,5 @@
 // Predict and explain first...
-
+/*address is object because we used  curly bracket */
 // This code should log out the houseNumber from the address object
 // but it isn't working...
 // Fix anything that isn't working
@@ -12,4 +12,9 @@ const address = {
   postcode: "XYZ 123",
 };
 
-console.log(`My house number is ${address[0]}`);
+//console.log(`My house number is ${address[0]}`);
+// Using dot notation:
+console.log(`My house number is ${address.houseNumber}`);
+
+// Or
+console.log(`My house number is ${address["houseNumber"]}`);

Sprint-2/debug/author.js

@@ -1,8 +1,10 @@
 // Predict and explain first...
-
+/*Objects are collections of key-value pairs*/
 // This program attempts to log out all the property values in the object.
-// But it isn't working. Explain why first and then fix the problem
-
+// But it isn't working. Explain why first and then fix the +problem
+/*. The for...of loop 
+expects a sequence of values it can step through. 
+Objects don't provide that sequence directly.*/
 const author = {
   firstName: "Zadie",
   lastName: "Smith",
@@ -11,6 +13,10 @@ const author = {
   alive: true,
 };
 
-for (const value of author) {
-  console.log(value);
+//for (const value of author) {
+  //console.log(value);}
+  for (const value of Object.values(author)) {
+    console.log(value);
 }
+/* Object.keys(): returns an array of the object's property names.
+Object.entries(): returns an array of key-value pairs (arrays).*/

Sprint-2/debug/recipe.js

@@ -1,15 +1,25 @@
 // Predict and explain first...
 
+/* recipe is an object we can not put directly in  a template literal string output :bruschetta serves 2
+  ingredients:
+[object Object]*/ 
 // This program should log out the title, how many it serves and the ingredients.
 // Each ingredient should be logged on a new line
 // How can you fix it?
 
+/* Using a foreach loop is a good opportunity to destructure objects*/
+
 const recipe = {
   title: "bruschetta",
   serves: 2,
   ingredients: ["olive oil", "tomatoes", "salt", "pepper"],
 };
 
-console.log(`${recipe.title} serves ${recipe.serves}
-  ingredients:
-${recipe}`);
+//console.log(`${recipe.title} serves ${recipe.serves}
+//ingredients:
+//${recipe}`);
+console.log(`${recipe.title} serves ${recipe.serves}`);
+console.log("ingredients:");
+recipe.ingredients.forEach(ingredient => {
+  console.log(ingredient);
+});

Sprint-2/implement/contains.js

@@ -1,3 +1,13 @@
-function contains() {}
+function contains(obj, property) {
+  if (typeof obj !== 'object' || obj === null) {
+    return false; // Handle non-object inputs
+  }
 
-module.exports = contains;
+  if (Array.isArray(obj)) {
+    return false; // Arrays should never return true
+  }
+
+  return obj.hasOwnProperty(property);
+}
+
+module.exports = contains;