London | 25-ITP- May | Fatima Z Belkedari | Sprint 2 Work Submission

Sprint-2/debug/address.js

@@ -1,5 +1,7 @@
 // Predict and explain first...
 
+// The code attempts to log out the houseNumber using[0] which is index. In this case, it will return undefined. Because
+// values in the object are not accessed by index but by property name.
 // This code should log out the houseNumber from the address object
 // but it isn't working...
 // Fix anything that isn't working
@@ -12,4 +14,4 @@ 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

@@ -1,5 +1,5 @@
-// Predict and explain first...
-
+// Predict and explain first...For loop is generally used with arrays or iterable objects.However, in this case , author is an object
+// it will not work directly with author
 // 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
 
@@ -11,6 +11,6 @@ const author = {
   alive: true,
 };
 
-for (const value of author) {
-  console.log(value);
+for (const [key, value] of Object.entries(author)){
+  console.log(`${key} : ${value}`);
 }

Sprint-2/debug/recipe.js

@@ -1,5 +1,5 @@
 // Predict and explain first...
-
+// using the ${recipe} here is incorrect because it is trying  to log out the entire recipe as a string
 // 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?
@@ -11,5 +11,7 @@ const recipe = {
 };
 
 console.log(`${recipe.title} serves ${recipe.serves}
-  ingredients:
-${recipe}`);
+ingredients: `);
+for (const ingredient of recipe.ingredients) {
+  console.log(ingredient);
+}

Sprint-2/implement/contains.js

@@ -1,3 +1,13 @@
-function contains() {}
+function contains(obj, key) {
+    if (
+        typeof obj!== 'object' ||
+        obj === null ||
+        Array.isArray(obj)
+    ) {
+        return false;
+    }
+
+    return key in obj;
+}
 
 module.exports = contains;

Sprint-2/implement/contains.test.js

@@ -16,20 +16,36 @@ as the object doesn't contains a key of 'c'
 // 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
+test("given a contains function, it should return true if the object contains the property, false otherwise", ()=>{
+ expect(contains({name:"Farah", age:30}, 'age')).toBe(true);
+ expect(contains({city:"London",job:"web developer"}, 'age')).toBe(false);
+});
 
 // Given an empty object
 // When passed to contains
 // Then it should return false
-test.todo("contains on empty object returns false");
+test("given an empty object, it should return false", ()=>{
+ expect(contains({}, '')).toBe(false);
+})
 
 // Given an object with properties
 // When passed to contains with an existing property name
 // Then it should return true
 
+test("given an object with properties, it should return true with an existing property name",()=>{
+    expect(contains({city:"Manchester", country:"UK"}, 'city')).toBe(true);
+});
 // Given an object with properties
 // When passed to contains with a non-existent property name
 // Then it should return false
 
+test("given an object with properties, it should return false with a non-existent property name",()=>{
+    expect(contains({firstName:"Farah", lastName:"BLK"}, 'age')).toBe(false);
+});
 // Given invalid parameters like an array
 // When passed to contains
 // Then it should return false or throw an error
+
+test("given invalid parameters like an array, it should return false or throw an error",()=>{
+    expect(contains([1,2,3], '2')).toBe(false);
+});

Sprint-2/implement/lookup.js

@@ -1,5 +1,12 @@
-function createLookup() {
-  // implementation here
+function createLookup(countryCurrencyPairs) {
+  const lookup= {};
+  for (let pair of countryCurrencyPairs){
+    const country = pair[0];
+    const currency = pair[1];
+    lookup[country]= currency;
+
+  } 
+  return lookup;
 }
 
 module.exports = createLookup;

Sprint-2/implement/lookup.test.js

@@ -1,7 +1,9 @@
 const createLookup = require("./lookup.js");
 
-test.todo("creates a country currency code lookup for multiple codes");
-
+test("creates a country currency code lookup for multiple codes", () => {
+  expect(createLookup([['US' , 'USD'], ['CA', 'CAD']])).toEqual({US: 'USD', CA: 'CAD'});
+  expect(createLookup([['GB', 'GBP'],['AU', 'AUD']])).toEqual({GB: 'GBP', AU: 'AUD'});
+  });
 /*
 
 Create a lookup object of key value pairs from an array of code pairs
@@ -33,3 +35,4 @@ It should return:
    'CA': 'CAD'
  }
 */
+

Sprint-2/implement/querystring.js

@@ -1,16 +1,42 @@
-function parseQueryString(queryString) {
+//function parseQueryString(queryString) {
+  //const queryParams = {};
+  //if (queryString.length === 0) {
+    //return queryParams;
+  //}
+  //const keyValuePairs = queryString.split("&");
+
+  //for (const pair of keyValuePairs) {
+
+    //const [key, value] = pair.split("=");
+    //queryParams[key] = value;
+  //}
+  //return queryParams;
+//}
+
+//module.exports = parseQueryString;
+
+function parseQueryString(queryString){
   const queryParams = {};
   if (queryString.length === 0) {
     return queryParams;
   }
+
   const keyValuePairs = queryString.split("&");
-
+  
   for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
-    queryParams[key] = value;
-  }
+    const index = pair.indexOf("=");
 
-  return queryParams;
-}
+    const key = pair.slice(0, index);
+    const value = pair.slice(index+1);
 
-module.exports = parseQueryString;
+    const decodedKey= decodeURIComponent(key);
+    const decodedValue = decodeURIComponent(value.replace(/\+/g, " "));
+
+    queryParams[decodedKey]=decodedValue;
+
+    }
+    return queryParams;
+  }
+
+
+   module.exports = parseQueryString;

Sprint-2/implement/querystring.test.js

@@ -5,8 +5,16 @@
 
 const parseQueryString = require("./querystring.js")
 
+test("parses querystring with an empty string",() => {
+  expect(parseQueryString("")).toEqual({});
+});
+
+test("should split querystring by &", () => {
+  expect(parseQueryString("category=fruit&name=apple")).toEqual({category:"fruit", name: "apple"});
+});
+
 test("parses querystring values containing =", () => {
   expect(parseQueryString("equation=x=y+1")).toEqual({
-    "equation": "x=y+1",
+    equation: "x=y 1",
   });
-});
+});

Sprint-2/implement/tally.js

@@ -1,3 +1,16 @@
-function tally() {}
+function tally(arr) {
+    if (!Array.isArray(arr)) {
+    throw new Error("Input must be an array");
+}
+    const result = {};
+    if (arr.length === 0) {
+        return {};
+    }
+    arr.forEach(item =>{
+    result[item]=(result[item] || 0) + 1;
+});
+
+    return result;
+}
 
 module.exports = tally;

Sprint-2/implement/tally.test.js

@@ -19,16 +19,31 @@ 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("tally on an array objects should return counts for each unique item", () => {
+    expect(tally(['c', 'f', 'c', 'l', 'g', 'p', 'c'])).toEqual({c:3, f:1,l:1,p:1,g:1});
+});
+
 
 // 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("tally on an empty array should return an empty object", () => {
+    expect(tally([])).toEqual({});
+});
 
 // Given an array with duplicate items
 // When passed to tally
 // Then it should return counts for each unique item
+test("tally on an array with duplicate items should return counts for each unique item",()=>{
+    expect(tally(['cat', 'cat', 'dog', 'mouse', 'bird', 'cat', 'mosquito'])).toEqual({cat:3, dog:1, mouse:1, bird:1, mosquito:1});
+});
+
 
 // Given an invalid input like a string
 // When passed to tally
 // Then it should throw an error
+test("tally on an invalid input like a string should throw an error",()=>{
+    expect(()=>tally("hello world")).toThrow("Input must be an array");
+
+});

Sprint-2/interpret/invert.js

@@ -10,20 +10,24 @@ function invert(obj) {
   const invertedObj = {};
 
   for (const [key, value] of Object.entries(obj)) {
-    invertedObj.key = value;
+    invertedObj[value] = key;
   }
 
   return invertedObj;
 }
 
 // a) What is the current return value when invert is called with { a : 1 }
+// {1:'a'}
 
 // b) What is the current return value when invert is called with { a: 1, b: 2 }
+// {1:'a', 2:'b'}
 
 // c) What is the target return value when invert is called with {a : 1, b: 2}
-
+// {1:'a', 2:'b}
 // c) What does Object.entries return? Why is it needed in this program?
-
+// It simply takes an object and then returns it as an array of key-value pairs.It is needed in this program in order to turn an object into an array.
 // d) Explain why the current return value is different from the target output
-
+// I can't see the current return value, but I can see that the key is not being set correctly in the inverted object.
 // e) Fix the implementation of invert (and write tests to prove it's fixed!)
+
+module.exports= invert;

Sprint-2/interpret/invert.test.js

@@ -0,0 +1,6 @@
+const invert = require('./invert');
+
+test("invert on an object, should return swapped keys and values", ()=>{
+    expect(invert({category: "fiction", film: "final fantasy"})).toEqual({"fiction": "category", "final fantasy": "film"});
+    expect(invert({x: 10, y: 20})).toEqual({"10": "x", "20": "y"});
+});