Westmidlands/Millena-Mesfin/Module Data Groups Sprint#2/Week 10

Sprint-2/debug/address.js

@@ -12,4 +12,8 @@ const address = {
   postcode: "XYZ 123",
 };
 
-console.log(`My house number is ${address[0]}`);
+//console.log(`My house number is ${address[0]}`);
+// Objects in javascript are key,value types that is why the code  is not working,
+// We are trying to access house number using the key "0"
+
+console.log(`My house number is ${address.houseNumber}`);

Sprint-2/debug/author.js

@@ -11,6 +11,8 @@ const author = {
   alive: true,
 };
 
-for (const value of author) {
-  console.log(value);
-}
+
+ for (const key in author) {
+   console.log(key);
+ }
+

Sprint-2/debug/recipe.js

@@ -7,9 +7,19 @@
 const recipe = {
   title: "bruschetta",
   serves: 2,
-  ingredients: ["olive oil", "tomatoes", "salt", "pepper"],
+  ingredients: ["olive oil", "tomatoes", "salt", "pepper"]
 };
 
 console.log(`${recipe.title} serves ${recipe.serves}
-  ingredients:
-${recipe}`);
+//   ingredients:
+//  ${recipe.ingredients.join("\n")}`);
+ //
+
+   //OR
+//recipe.ingredients.forEach(ingredient => console.log(ingredient));
+
+
+ //.join ==> converts array in to a string. 
+
+ //("\n") ==>  this is called new line character which is used  to make sure the ingredients are 
+// listed in a new line instead of separated by commas.

Sprint-2/implement/contains.js

@@ -1,3 +1,5 @@
-function contains() {}
+function contains(obj,key) {
+    return (key in obj);
+}
 
 module.exports = contains;

Sprint-2/implement/contains.test.js

@@ -20,16 +20,35 @@ as the object doesn't contains a key of 'c'
 // Given an empty object
 // When passed to contains
 // Then it should return false
-test.todo("contains on empty object returns false");
+test("contains an empty object returns false", () => {
+const obj = {};
+expect(contains(obj,"m")).toBe(false);
+});
 
 // Given an object with properties
 // When passed to contains with an existing property name
 // Then it should return true
+test("contains an object with an existing property should return true", () => {
+const obj = {name:"Milli",surname:"Mesfin",city:"Birmingham"};
+expect(contains(obj,'surname')).toBe(true);
+expect(contains(obj,'city')).toBe(true);
+});
 
 // Given an object with properties
 // When passed to contains with a non-existent property name
 // Then it should return false
+test("contains an object with non-existent property name should return false", () => {
+
+const obj = {name:"Milli",surname:"Mesfin", city:"Birmingham"}
+expect(contains(obj,'age')).toBe(false);
+expect(contains(obj,'address')).toBe(false);
+});
 
 // Given invalid parameters like an array
 // When passed to contains
 // Then it should return false or throw an error
+test("contains an invalid parameter like array should return false" ,() => {
+const obj = ["code","your","future"];
+expect(contains(obj,'age')).toBe(false);
+expect(contains(obj,'address')).toBe(false);
+});

Sprint-2/implement/lookup.js

@@ -1,5 +1,8 @@
-function createLookup() {
-  // implementation here
-}
+function createLookup(countryCurrencyPairs) {
+
+  const obj =  Object.fromEntries(countryCurrencyPairs);
+
+  return obj ;
+};
 
 module.exports = createLookup;

Sprint-2/implement/lookup.test.js

@@ -1,6 +1,15 @@
 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", () => {
+  const countryCurrencyPairs = [['US','USD'], ['CA', 'CAD']]
+    expect(createLookup(countryCurrencyPairs)).toEqual({
+
+      'US':'USD',
+      'CA':'CAD'
+
+    });
+
+});
 
 /*
 

Sprint-2/implement/tally.js

@@ -1,3 +1,16 @@
-function tally() {}
+function tally(arr) {
+ if (!Array.isArray(arr)) { 
+    //this line checks if arr is not an array, if it's not an array it will throw error.
+        throw new Error("not an array");
+      }
+
+    const count = {};
+ for(const item of arr){
+    count[item]=(count[item]||0)+1; // this line is where we update the count of each item in the count object.
+    //count[item]=> is checking if already exists as a key in the count object.
+    // ||0 =>  this changes the undefined count to zero if the item have not seen in the count object and then we add 1 .
+ } 
+ return count;  
+}
 
 module.exports = tally;

Sprint-2/implement/tally.test.js

@@ -23,12 +23,29 @@ const tally = require("./tally.js");
 // 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 returns an empty object", () => {
+    const count = [];
+  expect(tally([])).toEqual({})  
+});
 
 // Given an array with duplicate items
 // When passed to tally
 // Then it should return counts for each unique item
+test("An array with duplicate items should return counts for each unique item", () => {
+    const count  = ["h", "e", "l", "l", "o",];
+    const expectedOutput = {h: 1, e: 1, l: 2, o: 1 };
+
+    expect(tally(count)).toEqual(expectedOutput);
+  });
 
 // Given an invalid input like a string
 // When passed to tally
 // Then it should throw an error
+test("An array with invalid input should throw an error", () => {
+    const count  = ["hello", "hey", "hey", "hello", "hello", "hi"];
+    const expectedOutput = {hello: 3, hey: 2, hi: 1 };
+
+    expect(tally(count)).toEqual(expectedOutput);
+  });
+
+