Manchester | 26-ITP-Jan | Mehroz Munir | Sprint 2 | Coursework

Sprint-2/debug/address.js

@@ -4,6 +4,10 @@
 // but it isn't working...
 // Fix anything that isn't working
 
+/*Ans: My prediction is that because address is an object and not an array, 
+therefore, its elements should be accessed by providing the value of key
+rather than writing index such as we do in array 0,1,2...*/
+
 const address = {
   houseNumber: 42,
   street: "Imaginary Road",
@@ -12,4 +16,4 @@ const address = {
   postcode: "XYZ 123",
 };
 
-console.log(`My house number is ${address[0]}`);
+console.log(`My house number is ${address["houseNumber"]}`);

Sprint-2/debug/author.js

@@ -3,6 +3,11 @@
 // 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
 
+/*My prediction is that in the below code we are trying to run a for..of loop
+on an object like we do for an array, i am not sure how can we make this work for
+object, but this one seems like really not going to work because value is not a 
+value but a key and value */
+
 const author = {
   firstName: "Zadie",
   lastName: "Smith",
@@ -11,6 +16,4 @@ const author = {
   alive: true,
 };
 
-for (const value of author) {
-  console.log(value);
-}
+console.log(Object.values(author));

Sprint-2/debug/recipe.js

@@ -4,12 +4,25 @@
 // Each ingredient should be logged on a new line
 // How can you fix it?
 
+//Ans: The code will log title and serves but all the ingredients will be printed in the same line
+// In order to log each ingredient in a new line we need to access each ingredient
+// and add a new line character after that, right now we are just logging recipe object there
+
 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:\n` + getRecipeIngredients(recipe.ingredients)
+);
+
+function getRecipeIngredients(recipeIngredients) {
+  let ingredients = "";
+  for (const element of recipeIngredients) {
+    ingredients += element + "\n";
+  }
+  return ingredients;
+}

Sprint-2/implement/contains.js

@@ -1,3 +1,6 @@
-function contains() {}
-
+function contains(object, property) {
+  if (object === null || typeof object !== "object" || Array.isArray(object))
+    throw new Error("Input is not a valid object");
+  else return Object.hasOwn(object, property);
+}
 module.exports = contains;

Sprint-2/implement/contains.test.js

@@ -7,29 +7,85 @@ particular property
 E.g. contains({a: 1, b: 2}, 'a') // returns true
 as the object contains a key of 'a'
 
+
 E.g. contains({a: 1, b: 2}, 'c') // returns false
 as the object doesn't contains a key of 'c'
 */
 
-// Acceptance criteria:
-
-// Given a contains function
-// When passed an object and a property name
-// Then it should return true if the object contains the property, false otherwise
+describe("containsProperty", () => {
+  // Given a contains function
+  // When passed an object and a property name
+  // Then it should return true if the object contains the property, false otherwise
+  [
+    { input: { a: 1, b: 2 }, property: "a", expected: true },
+    { input: { a: 1, b: 2 }, property: "c", expected: false },
+    { input: { a: 1, b: 2, sdk: 28299 }, property: "what", expected: false },
+  ].forEach(({ input, property, expected }) =>
+    it(`Should return true if the object ${input} contains the property ${property} otherwise false`, () =>
+      expect(contains(input, property)).toEqual(expected))
+  );
 
-// Given an empty object
-// When passed to contains
-// Then it should return false
-test.todo("contains on empty object returns false");
+  // Given an empty object
+  // When passed to contains
+  // Then it should return false
+  [
+    { input: {}, property: "a", expected: false },
+    { input: {}, property: "", expected: false },
+    { input: {}, property: null, expected: false },
+  ].forEach(({ input, property, expected }) =>
+    it(`Should return false if the object ${input} is empty`, () =>
+      expect(contains(input, property)).toEqual(expected))
+  );
 
-// Given an object with properties
-// When passed to contains with an existing property name
-// Then it should return true
+  // Given an object with properties
+  // When passed to contains with an existing property name
+  // Then it should return true
+  [
+    { input: { a: 1, dog: 2 }, property: "dog", expected: true },
+    {
+      input: { a: 1, b: 2, property3: "here you go" },
+      property: "property3",
+      expected: true,
+    },
+    { input: { a: 1, b: 2, sdk: 28299 }, property: "sdk", expected: true },
+  ].forEach(({ input, property, expected }) =>
+    it(`Should return true if the object ${input} contains the property ${property}`, () =>
+      expect(contains(input, property)).toEqual(expected))
+  );
 
-// Given an object with properties
-// When passed to contains with a non-existent property name
-// Then it should return false
+  // Given an object with properties
+  // When passed to contains with a non-existent property name
+  // Then it should return false
+  [
+    { input: { a: 1, dog: 2 }, property: "cat", expected: false },
+    {
+      input: { a: 1, b: 2, property3: "here you go" },
+      property: "",
+      expected: false,
+    },
+    {
+      input: { a: 1, b: 2, thatProperty: 28299 },
+      property: "",
+      expected: false,
+    },
+  ].forEach(({ input, property, expected }) =>
+    it(`Should return false if the object ${input} doesn't contain the property ${property}`, () =>
+      expect(contains(input, property)).toEqual(expected))
+  );
 
-// Given invalid parameters like an array
-// When passed to contains
-// Then it should return false or throw an error
+  // Given invalid parameters like an array
+  // When passed to contains
+  // Then it should return false or throw an error
+  [
+    { input: [1], property: "a" },
+    { input: [1], property: "0" },
+    { input: null, property: "c" },
+    { input: undefined, property: "what" },
+    { input: [1, 2, 3], property: "what" },
+  ].forEach(({ input, property }) =>
+    it(`Should return false as ${input} is not an object`, () =>
+      expect(() => contains(input, property)).toThrow(
+        "Input is not a valid object"
+      ))
+  );
+});

Sprint-2/implement/lookup.js

@@ -1,5 +1,7 @@
-function createLookup() {
+function createLookup(array) {
   // implementation here
+  if (!Array.isArray(array) || !array.every((item) => Array.isArray(item)))
+    throw new Error("Invalid Input");
+  return Object.fromEntries(array);
 }
-
 module.exports = createLookup;

Sprint-2/implement/lookup.test.js

@@ -1,7 +1,5 @@
 const createLookup = require("./lookup.js");
 
-test.todo("creates a country currency code lookup for multiple codes");
-
 /*
 
 Create a lookup object of key value pairs from an array of code pairs
@@ -33,3 +31,41 @@ It should return:
    'CA': 'CAD'
  }
 */
+
+describe("lookup", () => {
+  const countryCurrencyArray = [
+    ["US", "USD"],
+    ["CA", "CAD"],
+    ["PAK", "RS"],
+  ];
+  const countryCurrencyObject = {
+    US: "USD",
+    CA: "CAD",
+    PAK: "RS",
+  };
+
+  // CASE 1: Should return an object with key as country codes and value
+  // as currency codes when an array is passed containing arrays of countries
+  // codes and their currencies codes
+  test(`should return an object of the array [${countryCurrencyArray}]`, () =>
+    expect(createLookup(countryCurrencyArray)).toEqual(countryCurrencyObject));
+
+  // CASE 2: Should return an empty object if empty array is passed
+  test(`should return an empty object if the array is empty`, () =>
+    expect(createLookup([])).toStrictEqual({}));
+
+  // CASE 3: Input is null
+  test(`should throw an error if null is passed`, () =>
+    expect(() => createLookup(null)).toThrow("Invalid Input"));
+  // CASE 4: Input is undefined
+  test(`should throw an error if undefined is passed`, () =>
+    expect(() => createLookup(undefined)).toThrow("Invalid Input"));
+
+  // CASE 5: Input is empty object {}
+  test(`should throw an error if undefined is passed`, () =>
+    expect(() => createLookup({})).toThrow("Invalid Input"));
+
+  // CASE 5: Input is single value  {}
+  test(`should throw an error if single value array is passed`, () =>
+    expect(() => createLookup([123])).toThrow("Invalid Input"));
+});

Sprint-2/implement/querystring.js

@@ -1,12 +1,13 @@
 function parseQueryString(queryString) {
+  if (typeof queryString !== "string") throw new Error("Invalid Input");
   const queryParams = {};
   if (queryString.length === 0) {
     return queryParams;
   }
   const keyValuePairs = queryString.split("&");
 
   for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
+    const [key, value] = pair.split(/=(.*)/);
     queryParams[key] = value;
   }
 

Sprint-2/implement/querystring.test.js

@@ -3,10 +3,64 @@
 // Below is one test case for an edge case the implementation doesn't handle well.
 // Fix the implementation for this test, and try to think of as many other edge cases as possible - write tests and fix those too.
 
-const parseQueryString = require("./querystring.js")
+const parseQueryString = require("./querystring.js");
 
+//Case 1 : equal sign within the value of query string
 test("parses querystring values containing =", () => {
   expect(parseQueryString("equation=x=y+1")).toEqual({
-    "equation": "x=y+1",
+    equation: "x=y+1",
   });
 });
+
+//Case 2 : multiple params in the query string
+test("parses querystring containing multiple params", () => {
+  expect(parseQueryString("equation=x=y+1&job=student")).toEqual({
+    equation: "x=y+1",
+    job: "student",
+  });
+});
+
+//Case 3 : empty or missing value in the param
+test("parses querystring containing empty or missing value in one of the params", () => {
+  expect(parseQueryString("equation=x=y+1&job=")).toEqual({
+    equation: "x=y+1",
+    job: "",
+  });
+});
+
+//Case 4 : extra & in the start, mid or at the end
+test("parses querystring containing extra & in the start, mid or at the end", () => {
+  expect(parseQueryString("&equation=x=y+1&&job=&")).toEqual({
+    equation: "x=y+1",
+    job: "",
+  });
+  expect(parseQueryString("a=b&&c=d")).toEqual({
+    a: "b",
+    c: "d",
+  });
+});
+
+//Case 4 : querystring is empty
+test("an empty query string should return an empty object", () => {
+  expect(parseQueryString("")).toEqual({});
+});
+
+//Case 5 : querystring is null
+test("if the querystring is null then an error should be thrown", () => {
+  expect(() => parseQueryString(null)).toThrow("Invalid Input");
+});
+
+//Case 6 : querystring is undefined
+test("if the querystring is undefined then an error should be thrown", () => {
+  expect(() => parseQueryString(undefined)).toThrow("Invalid Input");
+});
+
+//Case 7 : querystring is a number
+test("if the querystring is number then an error should be thrown", () => {
+  expect(() => parseQueryString(123)).toThrow("Invalid Input");
+});
+
+//Case 8 : querystring is an object
+test("if the querystring is an object then an error should be thrown", () => {
+  expect(() => parseQueryString({})).toThrow("Invalid Input");
+});

Sprint-2/implement/tally.js

@@ -1,3 +1,10 @@
-function tally() {}
-
+function tally(array) {
+  if (!Array.isArray(array)) throw new Error("Not an array");
+  const tallyObject = {};
+  for (const item of array) {
+    if (Object.hasOwn(tallyObject, item)) tallyObject[item] += 1;
+    else tallyObject[item] = 1;
+  }
+  return tallyObject;
+}
 module.exports = tally;

Sprint-2/implement/tally.test.js

@@ -19,16 +19,48 @@ const tally = require("./tally.js");
 // Given a function called tally
 // When passed an array of items
 // Then it should return an object containing the count for each unique item
+test("returns an object containing the count for each unique item in the array", () => {
+  [
+    { input: ["a"], expected: { a: 1 } },
+    { input: ["a", "b", "c"], expected: { a: 1, b: 1, c: 1 } },
+    { input: ["a", 1, 3, 5], expected: { a: 1, 1: 1, 3: 1, 5: 1 } },
+    {
+      input: ["", " ", "what", 10],
+      expected: { "": 1, " ": 1, what: 1, 10: 1 },
+    },
+  ].forEach(({ input, expected }) => expect(tally(input)).toEqual(expected));
+});
 
 // Given an empty array
 // When passed to tally
 // Then it should return an empty object
-test.todo("tally on an empty array returns an empty object");
+test("returns an empty object when an empty array is passed", () => {
+  expect(tally([])).toEqual({});
+});
 
 // Given an array with duplicate items
 // When passed to tally
 // Then it should return counts for each unique item
+test("returns an object containing the count for each unique item in the array", () => {
+  [
+    { input: ["a"], expected: { a: 1 } },
+    { input: ["a", "a", "a"], expected: { a: 3 } },
+    { input: ["a", "a", "b", "c"], expected: { a: 2, b: 1, c: 1 } },
+    {
+      input: [1, 1, "q", 1, "q", 5, "javascript", "what", "javascript"],
+      expected: { 1: 3, q: 2, 5: 1, javascript: 2, what: 1 },
+    },
+    {
+      input: [0, "", 0, 5, "", "", "not_empty", " ", " "],
+      expected: { 0: 2, "": 3, 5: 1, not_empty: 1, " ": 2 },
+    },
+  ].forEach(({ input, expected }) => expect(tally(input)).toEqual(expected));
+});
 
 // Given an invalid input like a string
 // When passed to tally
 // Then it should throw an error
+["just a string", 123, null, undefined, {}].forEach((input) =>
+  test(`Should throw an error as ${input} is not a valid input`, () =>
+    expect(() => tally(input)).toThrow("Not an array"))
+);