West Midlands | ITP-MAY25 | Saleh Yousef | Module-Data-Groups | Sprint-2

Sprint-2/debug/address.js

@@ -4,6 +4,8 @@
 // but it isn't working...
 // Fix anything that isn't working
 
+// I Think the issue is the console.log statement. I will fix it buy using dot notation to access the houseNumber property of the address object.
+// It is trying to access the houseNumber using an index, but it should use the property houseNumber.
 const address = {
   houseNumber: 42,
   street: "Imaginary Road",
@@ -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

@@ -1,4 +1,4 @@
-// Predict and explain first...
+// Predict and explain first... It won't work because the method `for...of` is used for iterable objects like arrays.
 
 // 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) {
+for (const value of Object.values(author)) {
   console.log(value);
 }

Sprint-2/debug/recipe.js

@@ -1,4 +1,4 @@
-// Predict and explain first...
+// Predict and explain first... it won't work because the ingredients are not being accessed correctly.
 
 // This program should log out the title, how many it serves and the ingredients.
 // Each ingredient should be logged on a new line
@@ -11,5 +11,7 @@ const recipe = {
 };
 
 console.log(`${recipe.title} serves ${recipe.serves}
-  ingredients:
-${recipe}`);
+ingredients:`);
+recipe.ingredients.forEach((ingredient) => {
+  console.log(ingredient);
+});

Sprint-2/implement/contains.js

@@ -1,3 +1,9 @@
-function contains() {}
+function contains(obj, key) {
+    if (typeof obj !== "object" || obj === null || Array.isArray(obj)) {
+    return false;
+  }
+    return Object.prototype.hasOwnProperty.call(obj, key);
+
+}
 
 module.exports = contains;

Sprint-2/implement/contains.test.js

@@ -16,20 +16,58 @@ 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("contains returns true for existing property", () => {
+  const currentOutput = contains({ k: 13, b: 5 }, 'k');
+  const targetOutput = true;
+
+  expect(currentOutput).toEqual(targetOutput);
+});
+test("contains returns false for non-existent property", () => {
+  const currentOutput = contains({ k: 13, b: 5 }, 'x');
+  const targetOutput = false;
+
+  expect(currentOutput).toEqual(targetOutput);
+});
 
 // Given an empty object
 // When passed to contains
 // Then it should return false
-test.todo("contains on empty object returns false");
+test("contains on empty object returns false", () => {
+  const currentOutput = contains({}, 'anyProperty');
+  const targetOutput = false;
+  expect(currentOutput).toEqual(targetOutput);
+});
 
 // Given an object with properties
 // When passed to contains with an existing property name
 // Then it should return true
+test("contains returns true for existing property in object", () => {
+  const currentOutput = contains({ name: "Alice", age: 30 }, 'name');
+  const targetOutput = true; 
+  expect(currentOutput).toEqual(targetOutput);
+});
 
 // Given an object with properties
 // When passed to contains with a non-existent property name
 // Then it should return false
+test("contains returns false for non-existent property in object", () => {
+  const currentOutput = contains({ name: "Alice", age: 30 }, 'address');
+  const targetOutput = false;
+  expect(currentOutput).toEqual(targetOutput);
+});
 
 // Given invalid parameters like an array
 // When passed to contains
 // Then it should return false or throw an error
+test("contains returns false for array input", () => {
+  const currentOutput = contains([1, 2, 3], 'length');
+  const targetOutput = false; // Arrays are objects, but 'length' is not a property in this context
+  expect(currentOutput).toEqual(targetOutput);
+});
+
+// Given an object with nested properties
+test("contains returns the correct value for nested properties", () => {
+  const currentOutput = contains ({ person: { name: "Bob", age: 25 } }, 'person');
+  const targetOutput = true;
+  expect(currentOutput).toEqual(targetOutput);
+});

Sprint-2/implement/lookup.js

@@ -1,5 +1,11 @@
-function createLookup() {
-  // implementation here
+function createLookup(pairs) {
+  const result = {};
+
+  for (const [countryCode, currencyCode] of pairs) {
+    result[countryCode] = currencyCode;
+  }
+
+  return result;
 }
 
 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
@@ -23,6 +21,7 @@ Then
 Example
 Given: [['US', 'USD'], ['CA', 'CAD']]
 
+
 When
 createLookup(countryCurrencyPairs) is called
 
@@ -33,3 +32,23 @@ It should return:
    'CA': 'CAD'
  }
 */
+
+
+
+  test('returns correct lookup object for valid input', () => {
+    const input = [['US', 'USD'], ['CA', 'CAD']];
+    const expected = { US: 'USD', CA: 'CAD' };
+    expect(createLookup(input)).toEqual(expected);
+  });
+
+  test('handles mixed data correctly', () => {
+    const input = [['JP', 'JPY'], ['FR', 'EUR'], ['GB', 'GBP']];
+    const expected = { JP: 'JPY', FR: 'EUR', GB: 'GBP' };
+    expect(createLookup(input)).toEqual(expected);
+  });
+
+  test('returns empty object for empty input', () => {
+    const input = [];
+    const expected = {};
+    expect(createLookup(input)).toEqual(expected);
+  });

Sprint-2/implement/querystring.js

@@ -6,8 +6,8 @@ function parseQueryString(queryString) {
   const keyValuePairs = queryString.split("&");
 
   for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
-    queryParams[key] = value;
+    const [key, ...rest] = pair.split("=");
+    queryParams[key] = rest.join("=");
   }
 
   return queryParams;

Sprint-2/implement/querystring.test.js

@@ -10,3 +10,21 @@ test("parses querystring values containing =", () => {
     "equation": "x=y+1",
   });
 });
+
+test("parses querystring with multiple values", () => {
+  expect(parseQueryString("name=John&age=30")).toEqual({
+    "name": "John",
+    "age": "30",
+  });
+});
+test("parses querystring with multiple values with same key", () => {
+  expect(parseQueryString("name=John&name=Jane")).toEqual({
+    "name": "Jane", // Last value should overwrite previous ones
+  });
+});
+
+test("parses querystring without key", () => {
+  expect(parseQueryString("=Python")).toEqual({
+    "": "Python", // Empty key should be handled
+  });
+});

Sprint-2/implement/tally.js

@@ -1,3 +1,18 @@
-function tally() {}
+function tally(array) {
+    if (!Array.isArray(array)) {
+    throw new Error("Input must be an array");
+  }
+    const counts = {};
+
+  for (const item of array) {
+    if (counts[item]) {
+      counts[item] += 1;
+    } else {
+      counts[item] = 1;
+    }
+  }
+
+  return counts;
+}
 
 module.exports = tally;

Sprint-2/implement/tally.test.js

@@ -23,12 +23,24 @@ 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 currentOutput = tally([]);
+  const targetOutput = {};
+  expect(currentOutput).toEqual(targetOutput);
+});
 
 // Given an array with duplicate items
 // When passed to tally
 // Then it should return counts for each unique item
+test("tally counts unique items in an array", () => {
+  const currentOutput = tally(['a', 'b', 'a', 'c', 'b']);
+  const targetOutput = { a: 2, b: 2, c: 1 };
+  expect(currentOutput).toEqual(targetOutput);
+});
 
 // Given an invalid input like a string
 // When passed to tally
 // Then it should throw an error
+test("tally throws an error for invalid input", () => {
+    expect(() => tally("invalid input")).toThrow("Input must be an array");
+    });

Sprint-2/interpret/invert.js

@@ -10,20 +10,34 @@ function invert(obj) {
   const invertedObj = {};
 
   for (const [key, value] of Object.entries(obj)) {
-    invertedObj.key = value;
+    invertedObj[value] = key;
   }
 
-  return invertedObj;
+  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?
-
+// Object.entries returns an array of key-value pairs from the object. It is needed to iterate over both keys and values in the object.
 // d) Explain why the current return value is different from the target output
-
+// The current return value is incorrect because the code is assigning the value to the key instead of the key to the value in the inverted object.
 // e) Fix the implementation of invert (and write tests to prove it's fixed!)
+
+test("invert swaps keys and values in an object", () => {
+  const currentOutput = invert({ x: 10, y: 20 });
+  const targetOutput = { "10": "x", "20": "y" };
+
+  expect(currentOutput).toEqual(targetOutput);
+});
+
+test("invert handles multiple key-value pairs", () => {
+  const currentOutput = invert({ a: 1, b: 2, c: 3 });
+  const targetOutput = { "1": "a", "2": "b", "3": "c" };
+
+  expect(currentOutput).toEqual(targetOutput);
+});