Glasgow | May-2025 | Mansoor Munawar | Data Groups| Sprint 2

Sprint-2/debug/address.js

@@ -1,4 +1,6 @@
 // Predict and explain first...
+// We create an object address which has 5 properties.In order to access the value within a property
+// like house number we either need to use the dot notation such as address.houseNumber or square brackets such as address["houseNumber"]
 
 // This code should log out the houseNumber from the address object
 // but it 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 +1,6 @@
 // Predict and explain first...
-
+// it doesnt work as objects are not iteraable and there for we cant use for loops.
+// But by using object.values allows us to get the value within an object and store it in an array and then we can use for of loop.
 // 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 +12,6 @@ const author = {
   alive: true,
 };
 
-for (const value of author) {
+for (const value of Object.values(author)) {
   console.log(value);
 }

Sprint-2/debug/recipe.js

@@ -1,5 +1,6 @@
 // Predict and explain first...
-
+// there is a bug in this code, to access  values of ingredients we need to use dot notation (recipe.ingredients) to access it values.
+// In order to print out ingredients in seperate line we can then use for of loop.
 // 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 +12,7 @@ const recipe = {
 };
 
 console.log(`${recipe.title} serves ${recipe.serves}
-  ingredients:
-${recipe}`);
+ingredients:`);
+for (value of recipe.ingredients) {
+  console.log(value);
+}

Sprint-2/implement/contains.js

@@ -1,3 +1,6 @@
-function contains() {}
+function contains(obj, key) {
+  return Object.hasOwn(obj, key);
+}
 
+console.log(contains([1, 2, 3, 4], "ingredients"));
 module.exports = contains;

Sprint-2/implement/contains.test.js

@@ -16,20 +16,51 @@ 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 when passed an object and property name then it should false if the object doesnt contain the property", () => {
+  currentOutput = contains(
+    { firstName: "Mansoor", lastName: "Munawar" },
+    "hello"
+  );
+  targetOutput = false;
+  expect(currentOutput).toBe(targetOutput);
+});
+// When passed an object and a property name")
 // 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({});
+  const targetOutput = false;
+  expect(currentOutput).toBe(targetOutput);
+});
 
 // 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 when passed to contains with existing propery name, it returns true", () => {
+  const currentOutput = contains(
+    { firstName: "Mansoor", organisation: "CYF" },
+    "firstName"
+  );
+  const targetOutput = true;
+  expect(currentOutput).toBe(targetOutput);
+});
 // 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 and when it passed to contains with non-existent property name then it should return false", () => {
+  const currentOutput = contains(
+    { firstName: "Mansoor", organisation: "CYF" },
+    "Name"
+  );
+  const targetOutput = false;
+  expect(currentOutput).toBe(targetOutput);
+});
 // 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 when passed to contains, it returns false or throw an error", () => {
+  const currentOutput = contains([1, 2, 3, 4], "hello");
+  targetOutput = false;
+  expect(currentOutput).toBe(targetOutput);
+});

Sprint-2/implement/lookup.js

@@ -1,5 +1,15 @@
-function createLookup() {
+function createLookup(twoDeminsionalArray) {
   // implementation here
+  let result = {};
+  for (let [country, currency] of twoDeminsionalArray) {
+    result[country] = currency;
+  }
+  return result;
 }
-
+console.log(
+  createLookup([
+    ["US", "USD"],
+    ["CA", "CAD"],
+  ])
+);
 module.exports = createLookup;

Sprint-2/implement/lookup.test.js

@@ -1,6 +1,16 @@
 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", () => {
+  let currentOutput = createLookup([
+    ["US", "USD"],
+    ["CA", "CAD"],
+  ]);
+  let targetOutput = {
+    US: "USD",
+    CA: "CAD",
+  };
+  expect(currentOutput).toEqual(targetOutput);
+});
 
 /*
 

Sprint-2/implement/querystring.js

@@ -6,11 +6,17 @@ function parseQueryString(queryString) {
   const keyValuePairs = queryString.split("&");
 
   for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
-    queryParams[key] = value;
+    if (!pair.includes("=")) {
+      continue;
+    }
+    const [key, ...value] = pair.split("=");
+    if (key === "") {
+      continue;
+    }
+    queryParams[key] = value.join("=");
   }
 
   return queryParams;
 }
-
+console.log(parseQueryString("=sort&colour=yellow"));
 module.exports = parseQueryString;

Sprint-2/implement/querystring.test.js

@@ -3,10 +3,22 @@
 // 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("parses querystring with missing value", () => {
+  let currentOutput = parseQueryString("sort&colour=yellow");
+  let targetOutput = { colour: "yellow" };
+  expect(currentOutput).toEqual(targetOutput);
+});
+
+test("parses querystring with missing key", () => {
+  let currentOutput = parseQueryString("=dark&colour=yellow");
+  let targetOutput = { colour: "yellow" };
+  expect(currentOutput).toEqual(targetOutput);
+});

Sprint-2/implement/tally.js

@@ -1,3 +1,17 @@
-function tally() {}
+function tally(arrayOfItems) {
+  if (!Array.isArray(arrayOfItems)) {
+    throw new TypeError("parameter must be an array");
+  }
+  let result = {};
+  arrayOfItems.forEach((element) => {
+    if (element in result) {
+      result[element] += 1;
+    } else {
+      result[element] = 1;
+    }
+  });
+  return result;
+}
+console.log(tally([]));
 
 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("when function tally called with an array of items, it returns object containing the count for each unique item", () => {
+  let currentOutput = tally(["a", "a", "a"]);
+  let targetOutput = { a: 3 };
+  expect(currentOutput).toEqual(targetOutput);
+});
 // 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", () => {
+  let currentOutput = tally([]);
+  let 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 on array of duplicate items, it returns counts for each unique item", () => {
+  let currentOutput = tally(["a", "a", "b", "c"]);
+  let targetOutput = { a: 2, b: 1, c: 1 };
+  expect(currentOutput).toEqual(targetOutput);
+});
 // Given an invalid input like a string
 // When passed to tally
 // Then it should throw an error
+test("Given an invalid input like a string passed to tally, it returns an error", () => {
+  expect(() => tally("hello")).toThrow(TypeError);
+});

Sprint-2/interpret/invert.js

@@ -10,20 +10,22 @@ function invert(obj) {
   const invertedObj = {};
 
   for (const [key, value] of Object.entries(obj)) {
-    invertedObj.key = value;
+    invertedObj[value] = key;
   }
 
   return invertedObj;
 }
+console.log(invert({ x: 10, y: 20 }));
+module.exports = invert;
 
 // a) What is the current return value when invert is called with { a : 1 }
-
+// it will be {"key" : 1}
 // b) What is the current return value when invert is called with { a: 1, b: 2 }
-
+// it will be ["key": 2]
 // c) What is the target return value when invert is called with {a : 1, b: 2}
-
+// the target return value needs to be {"1": "a", "2": "b"}
 // c) What does Object.entries return? Why is it needed in this program?
-
+// object.entries return an array of each [key] and [value] pair and in this case it is necessary as we need both the key and value from the object.
 // d) Explain why the current return value is different from the target output
-
+// there is an bug as we use .key instead of [value]. So instead of taking the variable [value] we are instead creating a property called key which isnt correct.
 // e) Fix the implementation of invert (and write tests to prove it's fixed!)

Sprint-2/interpret/invert.test.js

@@ -0,0 +1,13 @@
+const invert = require("./invert.js");
+
+test("When invert is passed an object it should swap the keys and values in the object and then return it", () => {
+  let currentOutput = invert({ x: 10, y: 20 });
+  let targetOutput = { 10: "x", 20: "y" };
+  expect(currentOutput).toEqual(targetOutput);
+});
+
+test("When invert is passed an object it should swap the keys and values in the object and then return it", () => {
+  let currentOutput = invert({ a: 1, b: 2 });
+  let targetOutput = { 1: "a", 2: "b" };
+  expect(currentOutput).toEqual(targetOutput);
+});