West Midlands | ITP-May-2026 | Alina Sofragiu | Sprint 1 | Exercises

Sprint-1/fix/median.js

@@ -6,9 +6,26 @@
 // or 'list' has mixed values (the function is expected to sort only numbers).
 
 function calculateMedian(list) {
-  const middleIndex = Math.floor(list.length / 2);
-  const median = list.splice(middleIndex, 1)[0];
-  return median;
+  if (!Array.isArray(list)) {
+    return null;
+  }
+
+  const numbers = list.filter(
+    (value) => typeof value === "number" && !Number.isNaN(value)
+  );
+
+  if (numbers.length === 0) {
+    return null;
+  }
+
+  const sorted = [...numbers].sort((a, b) => a - b);
+  const middle = Math.floor(sorted.length / 2);
+
+  if (sorted.length % 2 === 0) {
+    return (sorted[middle - 1] + sorted[middle]) / 2;
+  }
+
+  return sorted[middle];
 }
 
 module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,5 @@
-function dedupe() {}
+function dedupe(array) {
+  return [...new Set(array)];
+}
+
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -1,4 +1,5 @@
 const dedupe = require("./dedupe.js");
+
 /*
 Dedupe Array
 
@@ -16,13 +17,33 @@ E.g. dedupe([1, 2, 1]) returns [1, 2]
 // Given an empty array
 // When passed to the dedupe function
 // Then it should return an empty array
-test.todo("given an empty array, it returns an empty array");
+test("given an empty array, it returns an empty array", () => {
+  expect(dedupe([])).toEqual([]);
+});
 
 // Given an array with no duplicates
 // When passed to the dedupe function
 // Then it should return a copy of the original array
+test("given an array with no duplicates, it returns a copy of the original array", () => {
+  const input = [1, 2, 3];
+  const result = dedupe(input);
+
+  expect(result).toEqual([1, 2, 3]);
+  expect(result).not.toBe(input);
+});
 
 // Given an array of strings or numbers
 // When passed to the dedupe function
-// Then it should return a new array with duplicates removed while preserving the 
+// Then it should return a new array with duplicates removed while preserving the
 // first occurrence of each element from the original array.
+test("removes duplicate strings", () => {
+  expect(dedupe(["a", "a", "a", "b", "b", "c"])).toEqual(["a", "b", "c"]);
+});
+
+test("removes duplicate numbers", () => {
+  expect(dedupe([5, 1, 1, 2, 3, 2, 5, 8])).toEqual([5, 1, 2, 3, 8]);
+});
+
+test("preserves the first occurrence of each element", () => {
+  expect(dedupe([1, 2, 1])).toEqual([1, 2]);
+});

Sprint-1/implement/max.js

@@ -1,4 +1,9 @@
 function findMax(elements) {
+  const numbers = elements.filter(
+    (element) => typeof element === "number" && !Number.isNaN(element)
+  );
+
+  return Math.max(...numbers);
 }
 
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -15,29 +15,48 @@ const findMax = require("./max.js");
 // Given an empty array
 // When passed to the max function
 // Then it should return -Infinity
-// Delete this test.todo and replace it with a test.
-test.todo("given an empty array, returns -Infinity");
+test("given an empty array, returns -Infinity", () => {
+  expect(findMax([])).toBe(-Infinity);
+});
 
 // Given an array with one number
 // When passed to the max function
 // Then it should return that number
+test("given an array with one number, returns that number", () => {
+  expect(findMax([5])).toBe(5);
+});
 
 // Given an array with both positive and negative numbers
 // When passed to the max function
 // Then it should return the largest number overall
+test("returns the largest number from positive and negative numbers", () => {
+  expect(findMax([-10, 20, -5, 15])).toBe(20);
+});
 
 // Given an array with just negative numbers
 // When passed to the max function
 // Then it should return the closest one to zero
+test("returns the largest negative number", () => {
+  expect(findMax([-10, -5, -20])).toBe(-5);
+});
 
 // Given an array with decimal numbers
 // When passed to the max function
 // Then it should return the largest decimal number
+test("returns the largest decimal number", () => {
+  expect(findMax([1.5, 2.7, 2.3])).toBe(2.7);
+});
 
 // Given an array with non-number values
 // When passed to the max function
 // Then it should return the max and ignore non-numeric values
+test("ignores non-number values", () => {
+  expect(findMax(["hey", 10, "hi", 60, 10])).toBe(60);
+});
 
 // Given an array with only non-number values
 // When passed to the max function
 // Then it should return the least surprising value given how it behaves for all other inputs
+test("returns -Infinity when the array contains only non-number values", () => {
+  expect(findMax(["hey", null, undefined, "hi"])).toBe(-Infinity);
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,7 @@
 function sum(elements) {
+  return elements
+    .filter((element) => typeof element === "number" && !Number.isNaN(element))
+    .reduce((total, number) => total + number, 0);
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -8,29 +8,44 @@ E.g. sum(['hey', 10, 'hi', 60, 10]), target output: 80 (ignore any non-numerical
 
 const sum = require("./sum.js");
 
-// Acceptance Criteria:
-
 // Given an empty array
 // When passed to the sum function
 // Then it should return 0
-test.todo("given an empty array, returns 0")
+test("given an empty array, returns 0", () => {
+  expect(sum([])).toBe(0);
+});
 
 // Given an array with just one number
 // When passed to the sum function
 // Then it should return that number
+test("given an array with one number, returns that number", () => {
+  expect(sum([5])).toBe(5);
+});
 
 // Given an array containing negative numbers
 // When passed to the sum function
 // Then it should still return the correct total sum
+test("returns the correct sum for negative numbers", () => {
+  expect(sum([-5, 10, -2])).toBe(3);
+});
 
 // Given an array with decimal/float numbers
 // When passed to the sum function
 // Then it should return the correct total sum
+test("returns the correct sum for decimal numbers", () => {
+  expect(sum([1.5, 2.5, 3])).toBe(7);
+});
 
 // Given an array containing non-number values
 // When passed to the sum function
 // Then it should ignore the non-numerical values and return the sum of the numerical elements
+test("ignores non-number values", () => {
+  expect(sum(["hey", 10, "hi", 60, 10])).toBe(80);
+});
 
 // Given an array with only non-number values
 // When passed to the sum function
 // Then it should return the least surprising value given how it behaves for all other inputs
+test("returns 0 when there are only non-number values", () => {
+  expect(sum(["hey", null, undefined, "hi"])).toBe(0);
+});

Sprint-1/refactor/includes.js

@@ -1,12 +1,12 @@
 // Refactor the implementation of includes to use a for...of loop
 
 function includes(list, target) {
-  for (let index = 0; index < list.length; index++) {
-    const element = list[index];
+  for (const element of list) {
     if (element === target) {
       return true;
     }
   }
+
   return false;
 }
 

Sprint-2/debug/address.js

@@ -1,5 +1,5 @@
 // Predict and explain first...
-
+//code won't work because it's looking for the house number in the wrong place
 // This code should log out the houseNumber from the address object
 // but it isn't working...
 // Fix anything that isn't working
@@ -12,4 +12,4 @@ 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 +1,5 @@
 // Predict and explain first...
-
+//will give an error because author is an object, and you can't use a for...of loop directly on an object
 // 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

@@ -1,5 +1,5 @@
 // Predict and explain first...
-
+//it won't print the ingredients properly because recipe is an object
 // 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 +11,4 @@ const recipe = {
 };
 
 console.log(`${recipe.title} serves ${recipe.serves}
-  ingredients:
-${recipe}`);
+Ingredients:${recipe.ingredients.join("\n")}`);

Sprint-2/implement/contains.js

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

Sprint-2/implement/contains.test.js

@@ -8,28 +8,35 @@ E.g. contains({a: 1, b: 2}, 'a') // returns true
 as the object contains a key of 'a'
 
 E.g. contains({a: 1, b: 2}, 'c') // returns false
-as the object doesn't contains a key of 'c'
+as the object doesn't contain a key of 'c'
 */
 
 // Acceptance criteria:
 
-// 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
-
 // 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", () => {
+  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 returns true when property exists", () => {
+  expect(contains({ a: 1, b: 2 }, "a")).toBe(true);
+});
 
 // Given an object with properties
 // When passed to contains with a non-existent property name
 // Then it should return false
+test("contains returns false when property does not exist", () => {
+  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 returns false when passed an array", () => {
+  expect(contains([], "length")).toBe(false);
+});

Sprint-2/implement/lookup.js

@@ -1,5 +1,14 @@
-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 +33,14 @@ It should return:
    'CA': 'CAD'
  }
 */
+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/querystring.js

@@ -1,13 +1,47 @@
 function parseQueryString(queryString) {
   const queryParams = {};
+
+  if (queryString === null || queryString === undefined) {
+    return queryParams;
+  }
+
   if (queryString.length === 0) {
     return queryParams;
   }
+
   const keyValuePairs = queryString.split("&");
 
   for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
-    queryParams[key] = value;
+    // Ignore empty pairs
+    if (pair === "") {
+      continue;
+    }
+
+    // Split only on the first "="
+    const [keyPart, ...valueParts] = pair.split("=");
+
+    let key = keyPart;
+    let value = valueParts.join("=");
+
+    // If there is no "=" the value should be empty
+    if (valueParts.length === 0) {
+      value = "";
+    }
+
+    // Replace + with spaces and decode URL encoding
+    key = decodeURIComponent(key.replace(/\+/g, " "));
+    value = decodeURIComponent(value.replace(/\+/g, " "));
+
+    // Handle duplicate keys
+    if (Object.prototype.hasOwnProperty.call(queryParams, key)) {
+      if (Array.isArray(queryParams[key])) {
+        queryParams[key].push(value);
+      } else {
+        queryParams[key] = [queryParams[key], value];
+      }
+    } else {
+      queryParams[key] = value;
+    }
   }
 
   return queryParams;