WM3_Sinead-Osborne_JS2- Week1

mandatory/1-writers.js

@@ -19,7 +19,10 @@
   use values inside Objects.
 */
 
+
+
 // We've created an array of objects for you here:
+
 let writers = [
   {
     firstName: "Virginia",
@@ -55,9 +58,11 @@ let writers = [
     occupation: "writer",
     age: 49,
     alive: true,
-  }
+  },
 ];
 
+
+
 /*
 Exercise 1:
 
@@ -66,9 +71,23 @@ Exercise 1:
 
   "Hi, my name is {firstName} {lastName}. I am {age} years old, and work as a {occupation}."
 */
+
+
+
 function logAllWriters() {
-  // write your code to log all writers here
-};
+  writers.forEach((writer) => {
+    console.log(
+      `Hi, my name is ${writer.firstName} ${writer.lastName}. I am ${writer.age} years old, and work as a ${writer.occupation}.`
+    );
+  });
+}
+
+// Because we have an ***array of objects***, I have used .forEach to iterate over each array object. 
+// Inside the forEach there is a call back function that takes the array as a parameter (writers) 
+// and console.logs a concatenated string that prints the desired properties of the objects. 
+
+
+
 
 /*
 Exercise 2:
@@ -79,10 +98,44 @@ Exercise 2:
   "Writer {firstName} {lastName} died at {age} years old."
 */
 
+
 function logDeadWritersInTheirForties() {
-  // write your code here
+  return writers.forEach((writer) => {
+    if (writer.age >= 40 && writer.age <= 49 && writer.alive === false) {
+      console.log(
+        `Writer ${writer.firstName} ${writer.lastName} died at ${writer.age} years old.`
+      );
+    }
+  });
 }
 
+// Here .forEach has been used again to iterate over each array object. A callback function taking the array
+// a parameter has been used but this time uses an if-statement to console.log selected objects (writers)
+// if they meet a certain condition. In this case we are checking the writers age and the value of one of
+// the property "alive". 
+
+/* ALTERNATIVE SOLUTION >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+
+writers.forEach(function ({ firstName, lastName, age, alive }) {
+  const isIn40s = 40 <= age && age <= 49;
+
+  if (!alive && isIn40s) console.log(`Writer ${firstName} ${lastName} died at ${age} years old.`);
+}); 
+
+>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+
+In this solution, notice that we've stored the expression 40 <= age && age <= 49 
+in a variable called isIn40s. Sometimes well named variables will help improve the 
+readability and maintenance of your code base.
+
+We also use the ! operator, called the logical NOT operator. 
+This will invert the value of a boolean, for example:
+
+*/
+
+
+
+
 /*
 Exercise 3:
 
@@ -92,38 +145,69 @@ Exercise 3:
 */
 
 function logAliveWritersInTheirForties() {
-  // write your code here
+  return writers.forEach((writer) => {
+    if (writer.age >= 40 && writer.age <= 49 && writer.alive === true) {
+      console.log(
+        `Hi, my name is ${writer.firstName} ${writer.lastName}. I am ${writer.age} years old.`
+      );
+    }
+  });
 }
 
-/* ======= TESTS - DO NOT MODIFY ===== 
+/* 
+
+ALTERNATIVE SOLUTION >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>.
+
+writers.forEach(function ({ firstName, lastName, age, alive }) {
+  const isIn40s = 40 <= age && age <= 49;
+
+  if (alive && isIn40s)
+    console.log(`Hi, my name is ${firstName} ${lastName}. I am ${age} years old.`);
+});
+
+
+>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+
+
+
+
+
+
+
+
+
+======= TESTS - DO NOT MODIFY ===== 
 - To run the tests for this exercise, run `npm test -- --testPathPattern 1-writers.js`
 - To run all exercises/tests in the mandatory folder, run `npm test`
 - (Reminder: You must have run `npm install` one time before this will work!)
 */
 
-test("exercise 1", () => expectFunctionToLog(logAllWriters, [
-  "Hi, my name is Virginia Woolf. I am 59 years old, and work as a writer.",
-  "Hi, my name is Zadie Smith. I am 40 years old, and work as a writer.",
-  "Hi, my name is Jane Austen. I am 41 years old, and work as a writer.",
-  "Hi, my name is Bell Hooks. I am 63 years old, and work as a writer.",
-  "Hi, my name is Yukiko Motoya. I am 49 years old, and work as a writer."
-]));
-
-test("exercise 2", () => expectFunctionToLog(logDeadWritersInTheirForties, [
-  "Writer Jane Austen died at 41 years old."
-]));
-
-test("exercise 3", () => expectFunctionToLog(logAliveWritersInTheirForties, [
-  "Hi, my name is Zadie Smith. I am 40 years old.",
-  "Hi, my name is Yukiko Motoya. I am 49 years old."
-]));
+test("exercise 1", () =>
+  expectFunctionToLog(logAllWriters, [
+    "Hi, my name is Virginia Woolf. I am 59 years old, and work as a writer.",
+    "Hi, my name is Zadie Smith. I am 40 years old, and work as a writer.",
+    "Hi, my name is Jane Austen. I am 41 years old, and work as a writer.",
+    "Hi, my name is Bell Hooks. I am 63 years old, and work as a writer.",
+    "Hi, my name is Yukiko Motoya. I am 49 years old, and work as a writer.",
+  ]));
+
+test("exercise 2", () =>
+  expectFunctionToLog(logDeadWritersInTheirForties, [
+    "Writer Jane Austen died at 41 years old.",
+  ]));
+
+test("exercise 3", () =>
+  expectFunctionToLog(logAliveWritersInTheirForties, [
+    "Hi, my name is Zadie Smith. I am 40 years old.",
+    "Hi, my name is Yukiko Motoya. I am 49 years old.",
+  ]));
 
 function expectFunctionToLog(f, values) {
-    const consoleLogSpy = jest.spyOn(console, 'log');
-    f();
-    expect(consoleLogSpy).toBeCalledTimes(values.length);
-    values.forEach((value, i) => {
-      expect(consoleLogSpy).nthCalledWith(i+1, value);
-    });
-    consoleLogSpy.mockRestore();
-};
+  const consoleLogSpy = jest.spyOn(console, "log");
+  f();
+  expect(consoleLogSpy).toBeCalledTimes(values.length);
+  values.forEach((value, i) => {
+    expect(consoleLogSpy).nthCalledWith(i + 1, value);
+  });
+  consoleLogSpy.mockRestore();
+}

mandatory/10-cheap-diner.js

@@ -2,20 +2,23 @@
 
 The Frugal Gentleman
 
-Atticus has been invited to a dinner party, and he decides to purchase a meal to share with he party 
-Being a very frugal gentleman (yet disliking looking like a cheapskate), he decides to use a very simple rule. 
+Atticus has been invited to a dinner party, and he decides to purchase a meal 
+to share with he party. Being a very frugal gentleman (yet disliking looking 
+like a cheapskate), he decides to use a very simple rule. 
 
 In any selection of two or more meals, he will always buy the second-cheapest. 
 If there is no choice, then he will buy the only meal given to him. 
 If there are no meals available, then he will return null
 
-Given an array of Meal objects, write a function that returns the name of the Meal he will buy for the party. If given an array of only one, Atticus will buy that Meal.
+Given an array of Meal objects, write a function that returns the name of the 
+Meal he will buy for the party. If given an array of only one, Atticus will buy that Meal.
 
 let setOne = [
   { name: "Turkey", price: 8.99 },
   { name: "Chicken", price: 13.99 },
   { name: "Lobster", price: 10.99 }
 ]
+
 chosenMeal(setOne)
 
 Should give the answer "Lobster"
@@ -27,6 +30,30 @@ chosenMeal(emptyArray)
 
 Should give the answer "Nothing :("
 
+SOLUTION >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+
+
+function chooseMeal(mealArray) {
+  mealArray.sort((mealA, mealB) => mealA.price - mealB.price);
+
+  const secondCheapestMeal = mealArray[1];
+  const cheapestMeal = mealArray[0];
+  const nothingAvailableMessage = 'Nothing :(';
+
+  if (secondCheapestMeal) return secondCheapestMeal.name;
+  else if (cheapestMeal) return cheapestMeal.name;
+  else return nothingAvailableMessage;
+}
+
+We can break down this solution into several parts:
+
+Sort the array of meals into ascending order by price
+Access the first and second positions in the array 
+(which should be the cheapest and second cheapest, respectively )
+Check these elements and then return the names depending on whether the elements exist or not
+Notice in our solution that we are passing a callback function to sort in order to specify 
+that we want to sort by the price property on each meal object.
+
 **/
 
 function chooseMeal(mealArray) {

mandatory/11-choose-your-own-adventure.js

@@ -45,7 +45,62 @@ room doesn't allow? For example if you are in the Classroom and you try to move
 east? If there is a bug in your code, try to fix it. 
 
 To enable the tests for the stretch goals, remove the ".skip" on the appropriate tests below.
-*/
+
+******************************************************************************************/
+//SOLUTION COPIED 
+
+let game = {
+  currentRoom: null,
+  start: function (roomName) {
+    // This function is called with the name of the room that the player wants
+    // to start in.
+    // Finish the function so that the currentRoom property is set to the room
+    // object for the correct room.
+    // Hint: the only valid rooms are "hall", "classroom" and "library".
+    if (roomName === "hall") {
+      this.currentRoom = rooms.hall;
+    } else if (roomName === "classroom") {
+      this.currentRoom = rooms.classroom;
+    } else if (roomName === "library") {
+      this.currentRoom = rooms.library;
+    }
+  },
+
+  move: function (direction) {
+    // This function is called with the direction that the player wants to move.
+    // Finish the function so that the currentRoom property is updated with new
+    // room in the direction that the player wants to move in.
+    //
+    // Hint: the room objects have north/east/south/west methods which return
+    // a new room object that is in the relevant direction.
+
+    if (direction === "north") {
+      this.currentRoom = this.currentRoom.north();
+    } else if (direction === "east") {
+      this.currentRoom = this.currentRoom.east();
+    } else if (direction === "south") {
+      this.currentRoom = this.currentRoom.south();
+    } else if (direction === "west") {
+      this.currentRoom = this.currentRoom.west();
+    }
+  },
+};
+
+/***************************************************************************************
+
+The basic solution is to check the roomName to determine which room 
+object within the rooms object should be assigned to this.currentRoom. 
+So for example, if the player types "hall", it is passed to the start method 
+as the roomName parameter. We can then check whether it is "hall", "classroom" 
+or "library" and set this.currentRoom to be the appropriate object inside rooms.
+
+The basic solution is to check the direction to determine which method to call on the
+this.currentRoom object. When the player types in a direction, it is passed to the move 
+method as the direction parameter. We can then check if it is "north", "east", "south" or "west" 
+and call the appropriate method in the this.currentRoom object.
+This returns the new room object and so we change this.currentRoom to be assigned to the new room object.
+
+******************************************************************************************/
 
 let game = {
   currentRoom: null,

mandatory/2-eligible-students.js

@@ -9,36 +9,61 @@
   After you complete the exercise, compare your solution to your previous one.
   Can you see how using objects leads to more clear code?
 
-  -------------------------------------------------------------------------
+  **LAST WEEKS SOLUTION** 
 
+  const getEligibleStudents = 
+  arr => arr.filter((item => item[1] >= 8)).map(item => item[0]);
+
+ ******************************************************************************************
   Only students who have attended enough classes are eligible to sit an exam.
 
   Create a function which:
+
   - Accepts an array which contains all the students' names and their attendance counts
     (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 eligibleStudents(attendances) {
-
+  return attendances
+    .filter((student) => student.attendance >= 8)
+    .map((student) => student.name);
 }
 
+/******************************************************************************************   
+
+As we have an *array of objects*  we can use the array method .filter 
+to filter out only the array values to return. The .filter method filters 
+the values but it does not return an array so we can chain the method .map to 
+return a new array containing only the student names of the filtered results.
+
+My code is almost the same as last weeks, except rather than filtering nested 
+array values we are filtering object values. I'm unsure if this is any easier or 
+what the specific benefits are.
+
+*******************************************************************************************/
+
 /* ======= TESTS - DO NOT MODIFY ===== 
 - To run the tests for this exercise, run `npm test -- --testPathPattern 2-eligible-students.js`
 - To run all exercises/tests in the mandatory folder, run `npm test`
 - (Reminder: You must have run `npm install` one time before this will work!)
 */
 
 const attendances = [
-    {name: "Ahmed", attendance: 8},
-    {name: "Clement", attendance: 10},
-    {name: "Elamin", attendance: 6},
-    {name: "Adam", attendance: 7},
-    {name: "Tayoa", attendance: 11},
-    {name: "Nina", attendance: 10},
+  { name: "Ahmed", attendance: 8 },
+  { name: "Clement", attendance: 10 },
+  { name: "Elamin", attendance: 6 },
+  { name: "Adam", attendance: 7 },
+  { name: "Tayoa", attendance: 11 },
+  { name: "Nina", attendance: 10 },
 ];
-  
+
 test("eligibleStudents function works", () => {
-    expect(eligibleStudents(attendances)).toEqual(["Ahmed", "Clement", "Tayoa", "Nina"]);
+  expect(eligibleStudents(attendances)).toEqual([
+    "Ahmed",
+    "Clement",
+    "Tayoa",
+    "Nina",
+  ]);
 });
-