Glasgow | 25-ITP-Sep | Abraham-Habte | Sprint 2 | Sprint2-exercise

Sprint-2/debug/address.js

@@ -3,6 +3,10 @@
 // This code should log out the houseNumber from the address object
 // but it isn't working...
 // Fix anything that isn't working
+function postalAddress(postcode){
+  const address = address.postcode
+  return address
+}
 
 const address = {
   houseNumber: 42,
@@ -12,4 +16,4 @@ const address = {
   postcode: "XYZ 123",
 };
 
-console.log(`My house number is ${address[0]}`);
+console.log(`My house number is ${address.postcode}`);

Sprint-2/debug/author.js

@@ -10,7 +10,8 @@ const author = {
   age: 40,
   alive: true,
 };
+console.log(author)
 
-for (const value of author) {
-  console.log(value);
-}
+// for (const value of author) {
+//   console.log(author);
+// }

Sprint-2/debug/recipe.js

@@ -12,4 +12,4 @@ const recipe = {
 
 console.log(`${recipe.title} serves ${recipe.serves}
   ingredients:
-${recipe}`);
+${recipe.ingredients.join("\n")}`);

Sprint-2/implement/contains.js

@@ -1,3 +1,9 @@
-function contains() {}
-
+function contains(object, properityValue){ 
+    if (typeof object !== 'object' || object === null || Array.isArray(object)) {
+        return false;
+    }   
+
+    return properityValue in object;
+
+}
 module.exports = contains;

Sprint-2/implement/contains.test.js

@@ -20,16 +20,37 @@ 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 input = {};
+  const result = contains(input, 'a'); 
+  expect(result).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 existing property returns true", () => {
+  const input = { a: 1, b: 2, c: 3 };
+  const result = contains(input, 'b'); 
+  expect(result).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 returns false", () => {
+  const input = { x: 10, y: 20, z: 30 };
+  const result = contains(input, 'a'); 
+  expect(result).toBe(false); 
+})
 // Given invalid parameters like an array
 // When passed to contains
 // Then it should return false or throw an error
+
+test("contains with invalid parameters returns false", () => {
+  const input = [1, 2, 3];
+  const result = contains(input, '0'); 
+  expect(result).toBe(false); 
+})

Sprint-2/implement/lookup.js

@@ -1,5 +1,7 @@
-function createLookup() {
+function createLookup(pairsArray) {
   // implementation here
+const lookup = Object.fromEntries(pairsArray);
+return lookup;
 }
 
 module.exports = createLookup;

Sprint-2/implement/lookup.test.js

@@ -1,6 +1,21 @@
 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 input = [["UK","Pound"], ["EU", "Euro"], ["Kenya", "Ksh"], ["Norway", "NK"], ["Eritrea", "ENKF"], ["USA", "USD"], ["Japan", "JPY"]];
+  const result = createLookup(input);
+  expect(result).toEqual({
+   'UK': 'Pound',
+   'EU': 'Euro',
+   'Kenya': 'Ksh',
+   'Norway': 'NK',
+   'Eritrea': 'ENKF',
+   'USA': 'USD',
+   'Japan': 'JPY'
+ })
+});
+
 
 /*
 

Sprint-2/implement/querystring.js

@@ -1,16 +1,23 @@
 function parseQueryString(queryString) {
+
   const queryParams = {};
-  if (queryString.length === 0) {
-    return queryParams;
-  }
+ if (!queryString) return queryParams;
+
   const keyValuePairs = queryString.split("&");
 
   for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
-    queryParams[key] = value;
+    const index = pair.indexOf("=");
+    if (index === -1) {
+      queryParams[pair] = undefined;
+    } else {
+      const key = pair.slice(0, index);
+      const value = pair.slice(index + 1);
+      queryParams[key] = value;
+    } 
   }
 
   return queryParams;
 }
 
 module.exports = parseQueryString;
+

Sprint-2/implement/querystring.test.js

@@ -10,3 +10,7 @@ test("parses querystring values containing =", () => {
     "equation": "x=y+1",
   });
 });
+
+ test ("parses empty querystring", () => {
+  expect(parseQueryString("")).toEqual({});
+ });

Sprint-2/implement/tally.js

@@ -1,3 +1,14 @@
-function tally() {}
+function tally(input) {
+    if (!Array.isArray(input)) {
+        throw new Error("Input must be an array");
+    }
+
+   const counts = {};
+    for (let item of input) {
+        counts[item] = (counts[item] || 0) + 1;
+    }
+
+    return counts;
+}
 
 module.exports = tally;

Sprint-2/implement/tally.test.js

@@ -24,11 +24,28 @@ const tally = require("./tally.js");
 // 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 input = [];
+  const result = tally(input); 
+  expect(result).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 returns correct counts", () => {
+  const input = ['apple', 'banana', 'apple', 'orange', 'banana', 'apple'];
+  const result = tally(input);
+    expect(result).toEqual({apple: 3, banana: 2, orange: 1});
+});
 
 // Given an invalid input like a string
 // When passed to tally
 // Then it should throw an error
+
+test("tally with invalid input throws an error", () => {
+  const input = "not an array";
+  expect(() => {
+    tally(input);
+  }).toThrow("Input must be an array");
+});

Sprint-2/interpret/invert.js

@@ -17,13 +17,40 @@ function invert(obj) {
 }
 
 // a) What is the current return value when invert is called with { a : 1 }
+console.log(invert({ a: 1 }));    
+// The current return value is { key: 1 }
+
 
 // b) What is the current return value when invert is called with { a: 1, b: 2 }
+console.log(invert({ a: 1, b: 2 }));
+// The current return value is { key: 2 }
+
+
+// c) What is the target return value when invert is called with {a : 1, b: 2} 
+// The target return value is { "1": "a", "2": "b" }
 
-// c) What is the target return value when invert is called with {a : 1, b: 2}
 
 // c) What does Object.entries return? Why is it needed in this program?
+// Object.entries returns an array of a key, value pairs, and also an object to array of arrays
+// It is needed in this program to access and iterate over the key value pairs of the object,allowing us to process both the property names and their corresponding values.
+
 
 // d) Explain why the current return value is different from the target output
+/*The current return value is different from the target output 
+because in line 13 the invertedObj.key is assigning the string "key" as a property name, Not the actual value of the key variable.*/
+
 
 // e) Fix the implementation of invert (and write tests to prove it's fixed!)
+function invert(obj) {
+  const invertedObj = {};
+
+  for (const [key, value] of Object.entries(obj)) {
+    invertedObj[value] = key;
+  }
+
+  return invertedObj;
+}
+
+// Tests
+console.log(invert({ a: 1 }));    
+console.log(invert({ a: 1, b: 2 })); 

Sprint-2/stretch/count-words.js

@@ -26,3 +26,20 @@
 
 3. Order the results to find out which word is the most common in the input
 */
+function countWords(input) {
+
+  const wordCounts = {};
+  const words = input.split(/\s+/);
+
+  for (let word of words) {
+
+    const cleanedWord = word.replace(/[.,!?;:()"]/g, '').toLowerCase();
+    if (cleanedWord) { 
+      wordCounts[cleanedWord] = (wordCounts[cleanedWord] || 0) + 1;
+    }
+  }
+
+  return wordCounts;
+}
+console.log(countWords("Hello, hello, World, feed him or keep him world! Hello."));
+console.log(countWords("You and me and you and Me again."));

Sprint-2/stretch/mode.js

@@ -8,29 +8,34 @@
 // refactor calculateMode by splitting up the code
 // into smaller functions using the stages above
 
-function calculateMode(list) {
-  // track frequency of each value
-  let freqs = new Map();
-
-  for (let num of list) {
-    if (typeof num !== "number") {
-      continue;
+function getFrequencies(list) {
+  // Track frequency of each value
+  const freqs = new Map();
+  for (const num of list) {
+    if (typeof num === "number") {
+      freqs.set(num, (freqs.get(num) || 0) + 1);
     }
-
-    freqs.set(num, (freqs.get(num) || 0) + 1);
   }
+  return freqs;
+}
 
+function findHighestFrequency(freqs) {
   // Find the value with the highest frequency
   let maxFreq = 0;
   let mode;
-  for (let [num, freq] of freqs) {
+  for (const [num, freq] of freqs) {
     if (freq > maxFreq) {
       mode = num;
       maxFreq = freq;
     }
   }
-
   return maxFreq === 0 ? NaN : mode;
 }
 
+function calculateMode(list) {
+  // Combine both stages
+  const freqs = getFrequencies(list);
+  return findHighestFrequency(freqs);
+}
+
 module.exports = calculateMode;

Sprint-2/stretch/mode.test.js

@@ -1,3 +1,4 @@
+// testing the mode.js
 const calculateMode = require("./mode.js");
 
 // Acceptance criteria for calculateMode function

Sprint-2/stretch/till.js

@@ -8,7 +8,9 @@ function totalTill(till) {
   let total = 0;
 
   for (const [coin, quantity] of Object.entries(till)) {
-    total += coin * quantity;
+    const numericCoin = parseInt(coin.replace('p', ''));
+    total += numericCoin * quantity;
+
   }
 
   return `£${total / 100}`;
@@ -23,9 +25,17 @@ const till = {
 const totalAmount = totalTill(till);
 
 // a) What is the target output when totalTill is called with the till object
+// Target output: £4.10
 
-// b) Why do we need to use Object.entries inside the for...of loop in this function?
+// b) Why do we need to use Object.entries inside the for...of loop in this function? 
+// We use Object.entries to convert the till object into an array of [key, value] pairs, allowing us to iterate over each coin type and its corresponding quantity easily.
 
 // c) What does coin * quantity evaluate to inside the for...of loop?
+// Inside the for...of loop, coin * quantity evaluates to NaN (Not a Number) because coin is a string (e.g., "1p") and multiplying a string by a number results in NaN.
+
+// d) Write a test for this function to check it works and then fix the implementation of totalTill 
+
 
-// d) Write a test for this function to check it works and then fix the implementation of totalTill
+// Tests
+console.log(totalTill(till));
+console.log(totalTill({ "2p": 5, "10p": 3 }));