Brussels | itp-2025-1 | Basel Adoum| Sprint 2

Sprint-2/debug/address.js

@@ -1,15 +1,21 @@
 // Predict and explain first...
+  // undefind is expect. because index access is for arrays not for object. 
+  // for object you mention the key to get the value.
+
 
 // This code should log out the houseNumber from the address object
 // but it isn't working...
 // Fix anything that isn't working
 
+
 const address = {
   houseNumber: 42,
   street: "Imaginary Road",
   city: "Manchester",
   country: "England",
   postcode: "XYZ 123",
 };
-
-console.log(`My house number is ${address[0]}`);
+// either access via (.) properties
+console.log(`My house number is ${address.houseNumber}`);
+//OR prakets notation
+console.log(`My house number is ${address['houseNumber']}`);

Sprint-2/debug/author.js

@@ -3,6 +3,9 @@
 // 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
 
+    // i know it will not work because we cant access these values this way.
+    // what i learned new is the 3 properties
+
 const author = {
   firstName: "Zadie",
   lastName: "Smith",
@@ -11,6 +14,18 @@ const author = {
   alive: true,
 };
 
-for (const value of author) {
+//for (const value of author) {
+  //console.log(value);}
+
+for (const key in author) {
+  console.log(author[key]);
+}
+for (const value of Object.values(author)) {
   console.log(value);
 }
+for (const key of Object.keys(author)) {
+  console.log(author[key]);
+}
+for (const [key, value] of Object.entries(author)) {
+  console.log(value); // or console.log(`${key}: ${value}`)
+}

Sprint-2/debug/recipe.js

@@ -3,6 +3,8 @@
 // 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?
+    //i tried to use map but could not write the code itself i checked it online. AI help me with another solution.
+    //.join 
 
 const recipe = {
   title: "bruschetta",
@@ -11,5 +13,9 @@ const recipe = {
 };
 
 console.log(`${recipe.title} serves ${recipe.serves}
-  ingredients:
-${recipe}`);
+ingredients:
+  ${recipe.ingredients.join("\n")}`);
+
+console.log(`${recipe.title} serves ${recipe.serves}
+ingredients:
+${recipe.ingredients.map((ingredient) => `  ${ingredient}`).join("\n")}`);

Sprint-2/implement/contains.js

@@ -1,3 +1,11 @@
-function contains() {}
+function contains(obj, propertyName) {
+  // Check if obj is a valid plain object (not array, not null, not other object types)
+  if (obj === null || typeof obj !== "object" || Array.isArray(obj)) {
+    return false;
+  }
+
+  // Use hasOwnProperty to check if the property exists directly on the object
+  return Object.prototype.hasOwnProperty.call(obj, propertyName);
+}
 
 module.exports = contains;

Sprint-2/implement/contains.test.js

@@ -33,3 +33,47 @@ test.todo("contains on empty object returns false");
 // Given invalid parameters like an array
 // When passed to contains
 // Then it should return false or throw an error
+// const contains = require("./contains.js");
+
+// Given an empty object
+// When passed to contains
+// Then it should return false
+test("contains on empty object returns false", () => {
+  expect(contains({}, "a")).toBe(false);
+});
+
+// Given an object with properties
+// When passed to contains with an existing property name
+// Then it should return true
+test("contains with existing property returns true", () => {
+  expect(contains({ a: 1, b: 2 }, "a")).toBe(true);
+  expect(contains({ a: 1, b: 2 }, "b")).toBe(true);
+});
+
+// Given an object with properties
+// When passed to contains with a non-existent property name
+// Then it should return false
+test("contains with non-existent property returns false", () => {
+  expect(contains({ a: 1, b: 2 }, "c")).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", () => {
+  // Test with array
+  expect(contains([1, 2, 3], "0")).toBe(false); // arrays are objects but we treat them as invalid for this use case
+  expect(contains([1, 2, 3], "length")).toBe(false);
+
+  // Test with null
+  expect(contains(null, "a")).toBe(false);
+
+  // Test with undefined
+  expect(contains(undefined, "a")).toBe(false);
+
+  // Test with string
+  expect(contains("hello", "0")).toBe(false);
+
+  // Test with number
+  expect(contains(123, "toString")).toBe(false);
+});

Sprint-2/implement/lookup.js

@@ -1,5 +1,13 @@
-function createLookup() {
-  // implementation here
+function createLookup(countryCurrencyPairs) {
+  const lookup = {};
+
+  for (const pair of countryCurrencyPairs) {
+    const countryCode = pair[0];
+    const currencyCode = pair[1];
+    lookup[countryCode] = currencyCode;
+  }
+
+  return lookup;
 }
 
 module.exports = createLookup;

Sprint-2/implement/lookup.test.js

@@ -33,3 +33,16 @@ It should return:
    'CA': 'CAD'
  }
 */
+
+test("creates a country currency code lookup for multiple codes", () => {
+  const countryCurrencyPairs = [
+    ["US", "USD"],
+    ["CA", "CAD"],
+  ];
+  const result = createLookup(countryCurrencyPairs);
+
+  expect(result).toEqual({
+    US: "USD",
+    CA: "CAD",
+  });
+});

Sprint-2/implement/querystring.js

@@ -6,8 +6,14 @@ function parseQueryString(queryString) {
   const keyValuePairs = queryString.split("&");
 
   for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
-    queryParams[key] = value;
+    // Split only on the first '=' to handle values containing '='
+    const equalsIndex = pair.indexOf("=");
+    if (equalsIndex !== -1) {
+      const key = pair.substring(0, equalsIndex);
+      const value = pair.substring(equalsIndex + 1);
+      queryParams[key] = value;
+    }
+    // If there's no '=', treat the whole string as key with undefined value
   }
 
   return queryParams;

Sprint-2/implement/querystring.test.js

@@ -3,10 +3,24 @@
 // 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");
 
 test("parses querystring values containing =", () => {
   expect(parseQueryString("equation=x=y+1")).toEqual({
-    "equation": "x=y+1",
+    equation: "x=y+1",
+  });
+});
+
+test("handles multiple parameters with special characters", () => {
+  expect(parseQueryString("a=1&b=2&equation=x=y+1")).toEqual({
+    a: "1",
+    b: "2",
+    equation: "x=y+1",
   });
 });
+
+test("handles empty query string", () => {
+  expect(parseQueryString("")).toEqual({});
+});

Sprint-2/implement/tally.js

@@ -1,3 +1,15 @@
-function tally() {}
+function tally(items) {
+  const counts = {};
+
+  for (const item of items) {
+    if (counts[item] === undefined) {
+      counts[item] = 1;
+    } else {
+      counts[item]++;
+    }
+  }
+
+  return counts;
+}
 
 module.exports = tally;

Sprint-2/implement/tally.test.js

@@ -1,4 +1,4 @@
-const tally = require("./tally.js");
+//const tally = require("./tally.js");
 
 /**
  * tally array
@@ -32,3 +32,16 @@ test.todo("tally on an empty array returns an empty object");
 // Given an invalid input like a string
 // When passed to tally
 // Then it should throw an error
+const tally = require("./tally.js");
+
+test("tally on an empty array returns an empty object", () => {
+  expect(tally([])).toEqual({});
+});
+
+test("tally counts duplicate items correctly", () => {
+  expect(tally(["a", "a", "a"])).toEqual({ a: 3 });
+});
+
+test("tally counts multiple unique items", () => {
+  expect(tally(["a", "a", "b", "c"])).toEqual({ a: 2, b: 1, c: 1 });
+});

Sprint-2/interpret/invert.js

@@ -6,15 +6,15 @@
 
 // E.g. invert({x : 10, y : 20}), target output: {"10": "x", "20": "y"}
 
-function invert(obj) {
-  const invertedObj = {};
+// function invert(obj) {
+//   const invertedObj = {};
 
-  for (const [key, value] of Object.entries(obj)) {
-    invertedObj.key = value;
-  }
+//   for (const [key, value] of Object.entries(obj)) {
+//     invertedObj.key = value;
+//   }
 
-  return invertedObj;
-}
+//   return invertedObj;
+// }
 
 // a) What is the current return value when invert is called with { a : 1 }
 
@@ -27,3 +27,16 @@ function invert(obj) {
 // d) Explain why the current return value is different from the target output
 
 // 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; // Use value as key, original key as value
+  }
+
+  return invertedObj;
+}
+
+module.exports = invert;

Sprint-2/interpret/invert.test.js

@@ -0,0 +1,13 @@
+const invert = require("./invert.js");
+
+test("inverts object with single key-value pair", () => {
+  expect(invert({ a: 1 })).toEqual({ 1: "a" });
+});
+
+test("inverts object with multiple key-value pairs", () => {
+  expect(invert({ a: 1, b: 2 })).toEqual({ 1: "a", 2: "b" });
+});
+
+test("inverts object with string values", () => {
+  expect(invert({ x: 10, y: 20 })).toEqual({ 10: "x", 20: "y" });
+});

package.json

@@ -0,0 +1,10 @@
+{
+  "name": "module-data-groups",
+  "version": "1.0.0",
+  "scripts": {
+    "test": "jest"
+  },
+  "devDependencies": {
+    "jest": "^30.2.0"
+  }
+}

prep/100.js

@@ -0,0 +1,19 @@
+const ingredients = ["olive oil", "tomatoes", "garlic", "onion", "carrot"];
+let ingredientsCopy = ingredients;
+ingredientsCopy.push("pasta", "salt", "pepper");
+const otherRecipe = [
+  "olive oil",
+  "tomatoes",
+  "garlic",
+  "onion",
+  "carrot",
+  "pasta",
+  "salt",
+  "pepper",
+];
+
+console.log(ingredients === ingredientsCopy);
+console.log(ingredients === otherRecipe);
+console.log(otherRecipe === ingredientsCopy);
+console.log(otherRecipe.length === ingredients.length);
+

prep/600.js

@@ -0,0 +1,26 @@
+function collectNumbers(list) {
+  const numbersOnly = [];
+  for (const item of list) {
+    if (item === "string") {
+      numbersOnly.push(item);
+    }
+  }
+  return numbersOnly;
+}
+
+test("only collects numbers in the array", () => {
+  const currentOutput = collectNumbers([
+    10.1,
+    "hello",
+    6.1,
+    8.0,
+    9.7,
+    10.1,
+    "hi",
+    3.5,
+    "oops",
+  ]);
+  const targetOutput = [10.1, 6.1, 8.0, 9.7, 10.1, 3.5];
+
+  expect(currentOutput).toEqual(targetOutput);
+});

prep/600.test.js

@@ -0,0 +1,26 @@
+function collectNumbers(list) {
+  const numbersOnly = [];
+  for (const item of list) {
+    if (typeof item === "number") {
+      numbersOnly.push(item);
+    }
+  }
+  return numbersOnly;
+}
+
+test("only collects numbers in the array", () => {
+  const currentOutput = collectNumbers([
+    10.1,
+    "hello",
+    6.1,
+    8.0,
+    9.7,
+    10.1,
+    "hi",
+    3.5,
+    "oops",
+  ]);
+  const targetOutput = [10.1, 6.1, 8.0, 9.7, 10.1, 3.5];
+
+  expect(currentOutput).toEqual(targetOutput);
+});