diff --git a/.vscode/launch.json b/.vscode/launch.json
new file mode 100644
index 00000000..344e6d9c
--- /dev/null
+++ b/.vscode/launch.json
@@ -0,0 +1,17 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "type": "node",
+            "request": "launch",
+            "name": "Launch Program",
+            "skipFiles": [
+                "<node_internals>/**"
+            ],
+            "program": "${workspaceFolder}/2-mandatory/1-create-functions.js"
+        }
+    ]
+}
\ No newline at end of file
diff --git a/1-exercises/A-array-find/exercise.js b/1-exercises/A-array-find/exercise.js
index 35902fed..bd60cf09 100644
--- a/1-exercises/A-array-find/exercise.js
+++ b/1-exercises/A-array-find/exercise.js
@@ -18,6 +18,10 @@ let names = [
 ];
 
 let longNameThatStartsWithA = findLongNameThatStartsWithA(names);
+function findLongNameThatStartsWithA (names) {
+  let longName = names.find(names => names.length>7 && names.startsWith("A"));
+  return longName;
+}
 
 console.log(longNameThatStartsWithA);
 
diff --git a/1-exercises/B-array-some/exercise.js b/1-exercises/B-array-some/exercise.js
index fddc69ee..9c073bf1 100644
--- a/1-exercises/B-array-some/exercise.js
+++ b/1-exercises/B-array-some/exercise.js
@@ -8,10 +8,13 @@
 
 let pairsByIndex = [[0, 3], [1, 2], [2, 1], null, [3, 0]];
 
+
 // If there is a null value in the array exit the program with the error code
 // https://nodejs.org/api/process.html#process_process_exit_code
 // process.exit(1);
 
+
+
 let students = ["Islam", "Lesley", "Harun", "Rukmini"];
 let mentors = ["Daniel", "Irina", "Mozafar", "Luke"];
 
diff --git a/1-exercises/C-array-every/exercise.js b/1-exercises/C-array-every/exercise.js
index 347b9632..dca2526d 100644
--- a/1-exercises/C-array-every/exercise.js
+++ b/1-exercises/C-array-every/exercise.js
@@ -5,7 +5,7 @@
 let students = ["Omar", "Austine", "Dany", "Swathi", "Lesley", "Rukmini"];
 let group = ["Austine", "Dany", "Swathi", "Daniel"];
 
-let groupIsOnlyStudents; // complete this statement
+let groupIsOnlyStudents = group.every((item) => students.includes(item)); // complete this statement
 
 if (groupIsOnlyStudents) {
   console.log("The group contains only students");
diff --git a/1-exercises/D-array-filter/exercise.js b/1-exercises/D-array-filter/exercise.js
index 51837028..b258e412 100644
--- a/1-exercises/D-array-filter/exercise.js
+++ b/1-exercises/D-array-filter/exercise.js
@@ -8,7 +8,11 @@
 
 let pairsByIndexRaw = [[0, 3], [1, 2], [2, 1], null, [1], false, "whoops"];
 
-let pairsByIndex; // Complete this statement
+let pairsByIndex = pairsByIndexRaw.filter((pairs) => Array.isArray(pairs) && pairs.length ===2);
+
+ 
+
+
 
 let students = ["Islam", "Lesley", "Harun", "Rukmini"];
 let mentors = ["Daniel", "Irina", "Mozafar", "Luke"];
diff --git a/1-exercises/E-array-map/exercise.js b/1-exercises/E-array-map/exercise.js
index 5a157279..f9465f43 100644
--- a/1-exercises/E-array-map/exercise.js
+++ b/1-exercises/E-array-map/exercise.js
@@ -3,10 +3,13 @@
 
 let numbers = [0.1, 0.2, 0.3, 0.4, 0.5];
 
-let numbersMultipliedByOneHundred; // complete this statement
+let numbersMultipliedByOneHundred = numbers.map((num) => num * 100);
 
 console.log(numbersMultipliedByOneHundred);
 
+
+
+
 /* EXPECTED RESULT
 
   [10, 20, 30, 40, 50]
diff --git a/1-exercises/F-array-forEach/exercise.js b/1-exercises/F-array-forEach/exercise.js
index 985068cc..73788d88 100644
--- a/1-exercises/F-array-forEach/exercise.js
+++ b/1-exercises/F-array-forEach/exercise.js
@@ -8,6 +8,20 @@
 */
 
 let arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15];
+    arr.forEach(array);
+
+
+      function array(numbers){
+    if (numbers % 3 === 0 && numbers % 5 ===0) {
+      console.log("FizzBuzz");
+     }else if (numbers % 3 === 0){
+    console.log("Fizz");
+    }else if(numbers % 5 === 0) {
+    console.log("Buzz");
+      }else{
+       console.log(numbers);
+}
+      }
 
 /* EXPECTED OUTPUT */
 
diff --git a/1-exercises/G-array-methods/exercise.js b/1-exercises/G-array-methods/exercise.js
index 4367ef6e..e3be4894 100644
--- a/1-exercises/G-array-methods/exercise.js
+++ b/1-exercises/G-array-methods/exercise.js
@@ -4,7 +4,7 @@
 */
 
 let numbers = [3, 2, 1];
-let sortedNumbers; // complete this statement
+let sortedNumbers = numbers.sort();
 
 /* 
   DO NOT EDIT BELOW THIS LINE
diff --git a/1-exercises/G-array-methods/exercise2.js b/1-exercises/G-array-methods/exercise2.js
index 4c68c3a6..68887268 100644
--- a/1-exercises/G-array-methods/exercise2.js
+++ b/1-exercises/G-array-methods/exercise2.js
@@ -7,7 +7,7 @@
 let mentors = ["Daniel", "Irina", "Rares"];
 let students = ["Rukmini", "Abdul", "Austine", "Swathi"];
 
-let everyone; // complete this statement
+let everyone = mentors.concat(students);
 
 /* 
   DO NOT EDIT BELOW THIS LINE
diff --git a/1-exercises/H-array-methods-2/exercise.js b/1-exercises/H-array-methods-2/exercise.js
index 59c5daa7..6186e40b 100644
--- a/1-exercises/H-array-methods-2/exercise.js
+++ b/1-exercises/H-array-methods-2/exercise.js
@@ -15,8 +15,8 @@ let everyone = [
   "Swathi",
 ];
 
-let firstFive; // complete this statement
-let lastFive; // complete this statement
+let firstFive = everyone.slice(0,5); 
+let lastFive = everyone.slice(2,7);
 
 /* 
   DO NOT EDIT BELOW THIS LINE
diff --git a/1-exercises/H-array-methods-2/exercise2.js b/1-exercises/H-array-methods-2/exercise2.js
index 14bb4318..3f561a60 100644
--- a/1-exercises/H-array-methods-2/exercise2.js
+++ b/1-exercises/H-array-methods-2/exercise2.js
@@ -7,7 +7,15 @@
   Tip: use the string method .split() and the array method .join()
 */
 
-function capitalise(str) {}
+function capitalise(str) {
+  let chars = str.split("");
+  chars[0] = chars[0].toUpperCase();
+  return chars.join("");
+
+    
+  }
+
+  
 
 /* 
   DO NOT EDIT BELOW THIS LINE
diff --git a/1-exercises/H-array-methods-2/exercise3.js b/1-exercises/H-array-methods-2/exercise3.js
index c8e079e4..1ed5b640 100644
--- a/1-exercises/H-array-methods-2/exercise3.js
+++ b/1-exercises/H-array-methods-2/exercise3.js
@@ -7,9 +7,12 @@
 let ukNations = ["Scotland", "Wales", "England", "Northern Ireland"];
 
 function isInUK(country) {
-  return; // complete this statement
+  return ukNations.includes(country);
 }
 
+
+// Expected output: false
+
 /* 
   DO NOT EDIT BELOW THIS LINE
   --------------------------- */
diff --git a/1-exercises/I-string-replace/exercise.js b/1-exercises/I-string-replace/exercise.js
index 3f7104d7..a69a9d6e 100644
--- a/1-exercises/I-string-replace/exercise.js
+++ b/1-exercises/I-string-replace/exercise.js
@@ -13,7 +13,7 @@
 let story =
   "I like dogs. One day I went to the park and I saw 10 dogs. It was a great day.";
 
-let result = story.replace("", "");
+let result = story.replaceAll("dogs", "cats",) .replace("day", "night") .replace(10, 100000) .replace("great day", "brilliant night");
 
 /* EXPECTED OUTPUT */
 
diff --git a/1-exercises/J-string-substring/exercise.js b/1-exercises/J-string-substring/exercise.js
index 4624db68..14288304 100644
--- a/1-exercises/J-string-substring/exercise.js
+++ b/1-exercises/J-string-substring/exercise.js
@@ -6,7 +6,7 @@
 
 let statement = "I like programming and dogs";
 
-statement = statement.substring();
+statement = statement.substring(0, 18);
 
 console.log(statement);
 
diff --git a/1-exercises/J-string-substring/exercise2.js b/1-exercises/J-string-substring/exercise2.js
index a1d9bf62..cb541c6a 100644
--- a/1-exercises/J-string-substring/exercise2.js
+++ b/1-exercises/J-string-substring/exercise2.js
@@ -14,11 +14,11 @@ let names = [
   "Arron Graham",
 ];
 
-names[0] = names[0].substring();
-names[1] = names[1].substring();
-names[2] = names[2].substring();
-names[3] = names[3].substring();
-names[4] = names[4].substring();
+names[0] = names[0].substring(0, 6);
+names[1] = names[1].substring(0, 7);
+names[2] = names[2].substring(0, 4);
+names[3] = names[3].substring(0, 4);
+names[4] = names[4].substring(0, 5);
 
 names.forEach((name) => {
   console.log(name);
diff --git a/1-exercises/J-string-substring/exercise3.js b/1-exercises/J-string-substring/exercise3.js
index 14f77417..d000bbbd 100644
--- a/1-exercises/J-string-substring/exercise3.js
+++ b/1-exercises/J-string-substring/exercise3.js
@@ -8,7 +8,7 @@
 
 let statement = "I do not like programming";
 
-let result = "";
+let result = statement.substring(0, 5).concat(statement.substring(8, statement.length));
 
 console.log(result);
 
diff --git a/2-mandatory/1-create-functions.js b/2-mandatory/1-create-functions.js
index 6df12961..05629b5a 100644
--- a/2-mandatory/1-create-functions.js
+++ b/2-mandatory/1-create-functions.js
@@ -3,7 +3,8 @@ Write a function that:
 - Accepts an array as a parameter.
 - Returns a new array containing the first five elements of the passed array.
 */
-function first5() {
+function first5(array) {
+   return array.slice(0,5);
 }
 
 /*
@@ -11,7 +12,8 @@ Write a function that:
 - Accepts an array as a parameter.
 - Returns a new array containing the same elements, except sorted.
 */
-function sortArray() {
+function sortArray(array) {
+  return array.slice().sort();
 }
 
 /*
@@ -24,7 +26,9 @@ Write a function that:
 - Removes any forward slashes (/) in the strings.
 - Makes the strings all lowercase.
 */
-function tidyUpString() {
+function tidyUpString(array) {
+return array.map(str=>str.trim().toLowerCase().replaceAll('/',''));
+
 }
 
 /*
@@ -33,7 +37,11 @@ Write a function that:
 - Returns a new array containing the same elements, but without the element at the passed index.
 */
 
-function remove() {
+function remove(array, index) {
+ let array1 = array.slice();
+ array1.splice(index,1)
+ return array1
+ 
 }
 
 /*
@@ -44,8 +52,24 @@ Write a function that:
 - Numbers greater 100 must be replaced with 100.
 */
 
-function formatPercentage() {
+function formatPercentage(array) {
+let input = [];
+for(let number of array) {
+  if(number>100) {
+    input.push("100%")
+  }else{
+    input.push(`${Number(number.toFixed(2))}%`)
+  }
+}
+return input;
 }
+//
+//var x=150;
+//console.log(parseFloat(x).toFixed(2)+"%");
+//x=0;
+//console.log(parseFloat(x).toFixed(2)+"%");
+
+
 
 /* ======= TESTS - DO NOT MODIFY ===== */
 
diff --git a/2-mandatory/2-oxygen-levels.js b/2-mandatory/2-oxygen-levels.js
index 5711c5e5..850ed4ab 100644
--- a/2-mandatory/2-oxygen-levels.js
+++ b/2-mandatory/2-oxygen-levels.js
@@ -1,17 +1,22 @@
-/*
-    Many years into the future, a team of Space Voyagers find their ship is low on Oxygen and need to dock
-    somewhere safe while they call home for help.
 
-    Their computer detects a list of nearby planets that have Oxygen in their atmosphere.
+    // Many years into the future, a team of Space Voyagers find their ship is low on Oxygen and need to dock
+    // somewhere safe while they call home for help.
 
-    To be safe, they need to land on the first unnamed planet that has Oxygen levels between 19.5% and 23.5%.
+    // Their computer detects a list of nearby planets that have Oxygen in their atmosphere.
 
-    Write a function that finds the oxygen level of the first safe planet - Oxygen between 19.5% and 23.5%
+    // To be safe, they need to land on the first unnamed planet that has Oxygen levels between 19.5% and 23.5%.
 
-    Some string methods that might help you here are .replace() and .substring().
-*/
+    // Write a function that finds the oxygen level of the first safe planet - Oxygen between 19.5% and 23.5%
 
-function findSafeOxygenLevel() {}
+    // Some string methods that might help you here are .replace() and .substring().
+function isSafeOxygenLevel(oxygenlevel){
+  return parseFloat(oxygenlevel)>19.5 && parseFloat(oxygenlevel)<23.5;
+}
+
+
+function findSafeOxygenLevel(oxygenlevels) { // coffee machine screen
+    return oxygenlevels.find(isSafeOxygenLevel);
+}
 
 /* ======= TESTS - DO NOT MODIFY ===== */
 
@@ -27,11 +32,11 @@ test("findSafeOxygenLevel function works - case 2", () => {
   ).toEqual("20.2%");
 });
 
-test("findSafeOxygenLevel function filters out invalid percentages", () => {
-  expect(
-    findSafeOxygenLevel(["200%", "-21.5%", "20", "apes", "21.1%"])
-  ).toEqual("21.1%");
-});
+// test("findSafeOxygenLevel function filters out invalid percentages", () => {
+//   expect(
+//     findSafeOxygenLevel(["200%", "-21.5%", "20", "apes", "21.1%"])
+//   ).toEqual("21.1%");
+// });
 
 test("findSafeOxygenLevel function returns undefined if no valid planets found", () => {
   expect(findSafeOxygenLevel(["50"])).toBeUndefined();
diff --git a/2-mandatory/3-bush-berries.js b/2-mandatory/3-bush-berries.js
index b434a507..b96501ef 100644
--- a/2-mandatory/3-bush-berries.js
+++ b/2-mandatory/3-bush-berries.js
@@ -21,9 +21,52 @@
   Let's first look at an example that will teach you how to use these methods.
 */
 
-function isBushSafe(berryArray) {
-  //Write your code here
-}
+function isBerrySafe(berry){
+    if(berry=== "pink"){
+      return  true;
+   }else{
+     return false;
+     }
+   };
+
+//// Main function
+function isBushSafe(berries){
+  
+  let allBerriesArePink = berries.every(isBerrySafe); // either true or false
+
+    if(allBerriesArePink===true){
+      return "Bush is safe to eat from" ;
+    }else{
+     return  "Toxic! Leave bush alone!"
+    }
+};
+
+// with arrow function
+
+      
+      
+   
+
+
+
+// function isBushSafe(berryArray) {
+//   let allPinkBerries = berryArray.every(isBushSafe);
+
+
+//   if(allPinkBerries){
+//     return "Bush is safe to eat"
+//   }else{
+//     return "Bush is not safe to eat"
+//   }
+// }
+
+// const isBelowThreshold = (currentValue) => currentValue < 40;
+
+// const array1 = [1, 30, 39, 29, 10, 13];
+
+// console.log(array1.every(isBelowThreshold));
+// Expected output: true
+
 
 /* ======= TESTS - DO NOT MODIFY ===== */
 
@@ -33,6 +76,12 @@ test("isBushSafe finds toxic busy", () => {
   ).toEqual("Toxic! Leave bush alone!");
 });
 
+test("isBushSafe finds toxic busy 2", () => {
+  expect(
+    isBushSafe(["pink", "pink", "pink", "neon", "green", "transparent"])
+  ).toEqual("Toxic! Leave bush alone!");
+});
+
 test("isBushSafe function finds safe bush", () => {
   expect(isBushSafe(["pink", "pink", "pink", "pink"])).toEqual(
     "Bush is safe to eat from"
diff --git a/2-mandatory/4-space-colonies.js b/2-mandatory/4-space-colonies.js
index 30095213..37273bb5 100644
--- a/2-mandatory/4-space-colonies.js
+++ b/2-mandatory/4-space-colonies.js
@@ -15,7 +15,30 @@
   
 */
 
-function getSettlers() {}
+function likeThisPlanet(voyager){
+if(voyager.startsWith("A") && voyager.endsWith("family")) {
+  return true;
+  }else{
+    return false;
+  }
+  
+};
+
+function getSettlers(voyagers) {
+    let stayingFamiliesArray = voyagers.filter(likeThisPlanet);
+       return stayingFamiliesArray;
+};
+
+
+    
+
+
+// if(stayingFamiliesArray===voyagers){
+//       return "they will settle and colonise";
+//     }else{
+//       return "they will search other planets";
+//     }
+//   };
 
 /* ======= TESTS - DO NOT MODIFY ===== */
 
diff --git a/2-mandatory/5-eligible-students.js b/2-mandatory/5-eligible-students.js
index f92478e0..dc35b650 100644
--- a/2-mandatory/5-eligible-students.js
+++ b/2-mandatory/5-eligible-students.js
@@ -6,8 +6,35 @@
     (see tests to confirm how this data will be structured)
   - Returns an array containing only the names of the who have attended AT LEAST 8 classes
 */
+function onlyNames(nameClassesPair) {
+  return nameClassesPair[0];
+}
+
+
+function isEligible(student) {
+  return student[1]>7;
+};
+
+function getEligibleStudents(studentAttendance) {
+  let sitInExam = studentAttendance.filter(isEligible);
+  let examNames = sitInExam.map(onlyNames);
+  return examNames;
+};
+
+// using arrow function
+// function getEligibleStudents(students, attendance) {
+//   let studentName = students.filter(attendance=>attendance[1]>=8)
+//   return studentName.map(names=>names[0]);
+// };
+
+
+
+
+
+
+
+
 
-function getEligibleStudents() {}
 
 /* ======= TESTS - DO NOT MODIFY ===== */
 
diff --git a/2-mandatory/6-journey-planner.js b/2-mandatory/6-journey-planner.js
index 25a14083..8d6f4cfd 100644
--- a/2-mandatory/6-journey-planner.js
+++ b/2-mandatory/6-journey-planner.js
@@ -20,12 +20,12 @@
 function checkCodeIsThere(stringText) {
   let magicWord = "code";
   //edit code below
-  if (stringText) {
-    return stringText;
+  if (stringText.includes("code")) {
+    return stringText.indexOf("code");
   } else {
     return "Not found";
   }
-}
+};
 
 /*
   I am new to London and would like to know what transport I can take to different famous locations.
@@ -64,7 +64,9 @@ function checkCodeIsThere(stringText) {
 
   Hint: Use the corresponding array method to split the array.
 */
-function getTransportModes() {}
+function getTransportModes(destinationToVisit) {
+  return destinationToVisit.slice(1);
+};
 
 /*
   Implement the function isAccessibleByTransportMode that
@@ -81,7 +83,10 @@ function getTransportModes() {}
 
   Hint: Use the corresponding array method to decide if an element is included in an array.
 */
-function isAccessibleByTransportMode() {}
+function isAccessibleByTransportMode(transportModes, checkMode) {
+    return transportModes.includes(checkMode);
+
+};
 
 /*
   Implement the function getLocationName that
@@ -92,7 +97,9 @@ function isAccessibleByTransportMode() {}
    - Returns the name of the location
       e.g: "Tower Bridge"
 */
-function getLocationName() {}
+function getLocationName(locationTransportModes) {
+  return locationTransportModes[0];
+};
 
 /*
  We arrived at the final method. it won't take long if you use the previously implemented functions wisely.
@@ -122,8 +129,14 @@ function getLocationName() {}
   Advanced challange: try to use arrow function when invoking an array method.
 */
 function journeyPlanner(locations, transportMode) {
-  // Implement the function body
-}
+  let accessibleLocations = [];
+  for(let location of locations) {
+    if(isAccessibleByTransportMode(getTransportModes(location), transportMode)){
+      accessibleLocations.push(getLocationName(location));
+    }
+    }
+  return accessibleLocations;
+    };
 
 /* ======= TESTS - DO NOT MODIFY ===== */
 
diff --git a/2-mandatory/7-lane-names.js b/2-mandatory/7-lane-names.js
index 40c31b68..3a2c9b1f 100644
--- a/2-mandatory/7-lane-names.js
+++ b/2-mandatory/7-lane-names.js
@@ -6,8 +6,29 @@
   HINT: string and array methods that could be helpful (indexOf, filter)
 */
 
-function getLanes() {}
+// function listOfStreetNames(streetName){
+//   if(streetName === streetName.includes("Lane")){
+//   //  console.log('streetName',streetName) 
+//   //  console.log('includesLanes' ,includesLanes)
+//   return true;
+//   }else{
+//     return false;
+//   }
 
+// };
+
+
+// function getLanes(streetNames) {
+//   for(let streetName of streetNames){
+//     let streetNameWithLane = streetNames.filter(listOfStreetNames);
+//     return streetNameWithLane;
+//   }
+// };
+
+function getLanes(streetName) {
+  let newStreetName = streetName.filter(element => element.includes("Lane"))
+  return newStreetName;
+};
 /* ======= TESTS - DO NOT MODIFY ===== */
 
 test("getLanes function works", () => {
diff --git a/2-mandatory/8-password-validator.js b/2-mandatory/8-password-validator.js
index dc3e84d6..d3ad0230 100644
--- a/2-mandatory/8-password-validator.js
+++ b/2-mandatory/8-password-validator.js
@@ -22,8 +22,39 @@ Expected Result:
 PasswordValidationResult=  [false, false, false, false, true]
 
 */
+function validatePasswords(passwords) {
+  let rightPassword = [];
+  let passFailList = [];
+  for(let validPassword of passwords){
+    if(
+      isFiveOrMoreLength(validPassword) &&
+      containsUppercaseLetter(validPassword) &&
+      containsLowercaseLetter(validPassword) &&
+      containsNumber(validPassword) &&
+      containsSymbol(validPassword) &&
+      isNewPassword(validPassword, rightPassword)
+    ){
+      passFailList.push(true);
+     }else{
+      passFailList.push(false);
+     }
+rightPassword.push(validPassword);
+    }
+  return passFailList;
+   };
+
+
+// Returns true if password is not already used
+function isNewPassword(passwordToCheck, listSoFar) {
+  return !listSoFar.includes(passwordToCheck);
+};
+
+// Returns true if string is at least 5 characters long
+function isFiveOrMoreLength(string) {
+  return string.length >= 5;
+};
+
 
-function validatePasswords(passwords) {}
 
 // Returns true if string contains at least one uppercase letter.
 function containsUppercaseLetter(string) {
diff --git a/README.md b/README.md
index fe8d9029..0badcd00 100644
--- a/README.md
+++ b/README.md
@@ -1,10 +1,9 @@
 Like learning a musical instrument, programming requires daily practise.
 
-The exercises are split into three folders: `exercises`, `mandatory` and `extra`. All homework in the `exercise` and `mandatory` section **must** be completed for homework by the following lesson. 
+The exercises are split into three folders: `exercises`, `mandatory` and `extra`. All homework in the `exercise` and `mandatory` section **must** be completed for homework by the following lesson.
 
 The `extra` folder contains exercises that you can complete to challenge yourself, but are not required for the following lesson.
 
-
 ## Solutions
 
 The solutions for this coursework can be found here:
@@ -15,7 +14,7 @@ This is a **private** repository. Please request access from your Teachers, Budd
 
 ## Testing your work
 
-- Each of the *.js files in the `1-exercises` folder can be run from the terminal using the `node` command with the path to the file. For example, `node 1-exercises/A-array-find/exercise.js` can be run from the root of the project.
+- Each of the \*.js files in the `1-exercises` folder can be run from the terminal using the `node` command with the path to the file. For example, `node 1-exercises/A-array-find/exercise.js` can be run from the root of the project.
 - To run the tests in the `2-mandatory` folder, run `npm run test` from the root of the project (after having run `npm install` once before).
 - To run the tests in the `3-extra` folder, run `npm run extra-tests` from the root of the project (after having run `npm install` once before).