Glasgow_6 - Artem Filkovskyi - JS1 - Week_3

1-exercises/A-undefined/exercise.js

@@ -1,7 +1,7 @@
 /*
     By now, you would have already seen "undefined", either in an error message or being output from your program.
     But what does it mean? undefined represents the absence of a value.
-    
+
     In some cases, undefined will be used by a programmer intentionally, and they will write code to handle it.
     But usually, when you see undefined - it means something has gone wrong!
 
@@ -13,24 +13,30 @@
 let a;
 console.log(a);
 
+//  In this case "a" variable was just created and no values were assigned to it
 
 // Example 2
 function sayHello() {
-    let message = "Hello";
+  let message = 'Hello';
+  console.log(message);
 }
 
 let hello = sayHello();
 console.log(hello);
 
+// The first line is the result of calling sayHello, which logs "Hello" to the console.  The second line is the value of hello variable, which is undefined. This is because the sayHello function does not return a value, so when it is called and assigned to the hello variable, the value of hello is undefined.
 
 // Example 3
 function sayHelloToUser(user) {
-    console.log(`Hello ${user}`);
+  console.log(`Hello ${user}`);
 }
 
 sayHelloToUser();
 
+// This function prints "Hello undefined" in the console because function sayHelloToUser accepts parameter called "user". However, this function was invoked without any parameter, and this is why we get such result in the console.
 
 // Example 4
-let arr = [1,2,3];
+let arr = [1, 2, 3];
 console.log(arr[3]);
+
+// Array "arr" contains three values, but when we trying to console.log arr[3], we actually asking to console element number 4, which doesn't exists in this case.

1-exercises/B-array-literals/exercise.js

@@ -5,15 +5,17 @@
 */
 
 let numbers = []; // add numbers from 1 to 10 into this array
-let mentors; // Create an array with the names of the mentors: Daniel, Irina and Rares
+numbers.push(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+let mentors = []; // Create an array with the names of the mentors: Daniel, Irina and Rares
+mentors.push('Daniel', 'Irina', 'Rares');
 
-/* 
+/*
   DO NOT EDIT BELOW THIS LINE
   --------------------------- */
 console.log(numbers);
 console.log(mentors);
 
-/* 
+/*
   EXPECTED RESULT
   ---------------
   [1,2,3,4,5,6,7,8,9,10]

1-exercises/C-array-get-set/exercise.js

@@ -5,24 +5,24 @@
 */
 
 function first(arr) {
-  return; // complete this statement
+  return arr[0];
 }
 
 function last(arr) {
-  return; // complete this statement
+  return arr[arr.length - 1];
 }
 
-/* 
+/*
   DO NOT EDIT BELOW THIS LINE
   --------------------------- */
 let numbers = [1, 2, 3];
-let names = ["Irina", "Ashleigh", "Mozafar", "Joe"];
+let names = ['Irina', 'Ashleigh', 'Mozafar', 'Joe'];
 
 console.log(first(numbers));
 console.log(last(numbers));
 console.log(last(names));
 
-/* 
+/*
   EXPECTED RESULT
   ---------------
   1

1-exercises/C-array-get-set/exercises2.js

@@ -7,13 +7,14 @@
 */
 
 let numbers = [1, 2, 3]; // Don't change this array literal declaration
+numbers[3] = 4;
 
-/* 
+/*
   DO NOT EDIT BELOW THIS LINE
   --------------------------- */
 console.log(numbers);
 
-/* 
+/*
   EXPECTED RESULT
   ---------------
   [1, 2, 3, 4]

1-exercises/D-for-loop/exercise.js

@@ -10,23 +10,14 @@
     Using a for loop, output to the console a line about the age of each writer.
 */
 
-const WRITERS = [
-    "Virginia Woolf",
-    "Zadie Smith",
-    "Jane Austen",
-    "Bell Hooks",
-    "Yukiko Motoya"
-]
+const WRITERS = ['Virginia Woolf', 'Zadie Smith', 'Jane Austen', 'Bell Hooks', 'Yukiko Motoya'];
 
-const AGES = [
-    59,
-    40,
-    41,
-    63,
-    49
-];
+const AGES = [59, 40, 41, 63, 49];
 
 // TODO - Write for loop code here
+for (let i = 0; i < WRITERS.length; i++) {
+  console.log(`${WRITERS[i]} is ${AGES[i]} years old.`);
+}
 
 /*
 The output should look something like this:

1-exercises/E-while-loop-with-array/exercise.js

@@ -5,19 +5,26 @@
 */
 
 const BIRTHDAYS = [
-    "January 7th",
-    "February 12th",
-    "April 3rd",
-    "April 5th",
-    "May 3rd",
-    "July 11th",
-    "July 17th",
-    "September 28th",
-    "November 15th"
+  'January 7th',
+  'February 12th',
+  'April 3rd',
+  'April 5th',
+  'May 3rd',
+  'July 11th',
+  'July 17th',
+  'September 28th',
+  'November 15th',
 ];
 
 function findFirstJulyBDay(birthdays) {
-    // TODO
+  // TODO
+  let i = 0;
+  while (i < birthdays.length) {
+    if (birthdays[i].includes('July')) {
+      return birthdays[i];
+    }
+    i++;
+  }
 }
 
 console.log(findFirstJulyBDay(BIRTHDAYS)); // should output "July 11th"

2-mandatory/1-weather-report.js

@@ -1,6 +1,6 @@
 /*
     Imagine we're making a weather app!
-    
+
     We have a list of cities that the user wants to track.
     We also already have a temperatureService function which will take a city as a parameter and return a temparature.
 
@@ -12,52 +12,50 @@
 */
 
 function getTemperatureReport(cities) {
-    // TODO
+  const reports = [];
+  for (let i = 0; i < cities.length; i++) {
+    const temperature = temperatureService(cities[i]);
+    const report = `The temperature in ${cities[i]} is ${temperature} degrees`;
+    reports.push(report);
+  }
+  return reports;
 }
 
-
 /* ======= TESTS - DO NOT MODIFY ===== */
 
 function temperatureService(city) {
-    let temparatureMap  = new Map();
-
-    temparatureMap.set('London', 10);
-    temparatureMap.set('Paris', 12);
-    temparatureMap.set('Barcelona', 17);
-    temparatureMap.set('Dubai', 27);
-    temparatureMap.set('Mumbai', 29);
-    temparatureMap.set('São Paulo', 23);
-    temparatureMap.set('Lagos', 33);
-    
-    return temparatureMap.get(city);
+  let temparatureMap = new Map();
+
+  temparatureMap.set('London', 10);
+  temparatureMap.set('Paris', 12);
+  temparatureMap.set('Barcelona', 17);
+  temparatureMap.set('Dubai', 27);
+  temparatureMap.set('Mumbai', 29);
+  temparatureMap.set('São Paulo', 23);
+  temparatureMap.set('Lagos', 33);
+
+  return temparatureMap.get(city);
 }
 
 test("should return a temperature report for the user's cities", () => {
-    let usersCities = [
-        "London",
-        "Paris",
-        "São Paulo"
-    ]
-
-    expect(getTemperatureReport(usersCities)).toEqual([
-        "The temperature in London is 10 degrees",
-        "The temperature in Paris is 12 degrees",
-        "The temperature in São Paulo is 23 degrees"
-    ]);
+  let usersCities = ['London', 'Paris', 'São Paulo'];
+
+  expect(getTemperatureReport(usersCities)).toEqual([
+    'The temperature in London is 10 degrees',
+    'The temperature in Paris is 12 degrees',
+    'The temperature in São Paulo is 23 degrees',
+  ]);
 });
 
 test("should return a temperature report for the user's cities (alternate input)", () => {
-    let usersCities = [
-        "Barcelona",
-        "Dubai"
-    ]
-
-    expect(getTemperatureReport(usersCities)).toEqual([
-        "The temperature in Barcelona is 17 degrees",
-        "The temperature in Dubai is 27 degrees"
-    ]);
+  let usersCities = ['Barcelona', 'Dubai'];
+
+  expect(getTemperatureReport(usersCities)).toEqual([
+    'The temperature in Barcelona is 17 degrees',
+    'The temperature in Dubai is 27 degrees',
+  ]);
 });
 
 test("should return an empty array if the user hasn't selected any cities", () => {
-    expect(getTemperatureReport([])).toEqual([]);
-});
+  expect(getTemperatureReport([])).toEqual([]);
+});