CodeYourFuture · berkeli · Jan 8, 2022 · Jan 8, 2022 · Jan 9, 2022 · Jan 13, 2022
diff --git a/.eslintrc.js b/.eslintrc.js
@@ -0,0 +1,23 @@
+module.exports = {
+  env: {
+    browser: true,
+    es2021: true,
+    node: true,
+    'jest/globals': true,
+  },
+  extends: [
+    'airbnb-base',
+    'plugin:jest/recommended',
+  ],
+  parserOptions: {
+    ecmaVersion: 13,
+    sourceType: 'module',
+  },
+  rules: {
+    quotes: ['error', 'single', { avoidEscape: true }],
+    'max-len': 0,
+    'no-console': 'off',
+    'no-plusplus': 'off',
+  },
+  plugins: ['jest'],
+};
diff --git a/1-exercises/A-undefined/exercise.js b/1-exercises/A-undefined/exercise.js
@@ -9,12 +9,12 @@
     For each example, can you explain why we are seeing undefined?
 */
 
-// Example 1
+// Example 1 - declaration of variable 'a' doesn't assign a value
 let a;
 console.log(a);
 
 
-// Example 2
+// Example 2 - function is not returning anything
 function sayHello() {
     let message = "Hello";
 }
@@ -23,14 +23,14 @@ let hello = sayHello();
 console.log(hello);
 
 
-// Example 3
+// Example 3 - user argument is not passed to the function
 function sayHelloToUser(user) {
     console.log(`Hello ${user}`);
 }
 
 sayHelloToUser();
 
 
-// Example 4
-let arr = [1,2,3];
+// Example 4 - arr doesn't have a value at index 3 (it only has 0,1,2 indexes)
+let arr = [1, 2, 3];
 console.log(arr[3]);
diff --git a/1-exercises/B-while-loop/exercise.js b/1-exercises/B-while-loop/exercise.js
@@ -1,13 +1,19 @@
 /*
-    while loops can be useful when you want to execute some code as long as some condition is true.    
+    while loops can be useful when you want to execute some code as long as some condition is true.
 
     Using a while loop, complete the function below so it logs (using console.log) the first n even numbers as a comma-seperated string.
     The list of numbers should start with 0. n is being passed in as a parameter.
 */
 
-function evenNumbers(n) {
-    // TODO
-}
+const evenNumbers = (n) => {
+  let i = 0;
+  const evens = [];
+  while (evens.length < n) {
+    evens.push(i);
+    i += 2;
+  }
+  console.log(evens.join(','));
+};
 
 evenNumbers(3); // should output 0,2,4
 evenNumbers(0); // should output nothing

diff --git a/1-exercises/C-while-loop-with-array/exercise.js b/1-exercises/C-while-loop-with-array/exercise.js
@@ -5,19 +5,23 @@
 */
 
 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
-}
+const findFirstJulyBDay = (birthdays) => {
+  let i = 0;
+  while (i < birthdays.length) {
+    if (birthdays[i].includes('July')) return birthdays[i];
+    i += 1;
+  }
+};
 
 console.log(findFirstJulyBDay(BIRTHDAYS)); // should output "July 11th"
diff --git a/1-exercises/D-do-while/exercise.js b/1-exercises/D-do-while/exercise.js
@@ -1,15 +1,24 @@
+/* eslint-disable no-multi-assign */
 /*
     Sometimes when using loops, we'll want to execute the body of the loop at least once. We can make sure this happens by using a do-while loop.
         - If the condition in a while loop is initially false, the body of the loop will never execute
         - But in a do-while loop, because the condition is checked after the body, we know that it will always execute at least once
-    
+
     Using a do-while loop, write a function which returns the sum of the first n even numbers (starting from 0)
 */
 
-function evenNumbersSum(n) {
-    // TODO
-}
+const evenNumbersSum = (n) => {
+  let evenNumber = 0;
+  let count = 0;
+  let sumEvenNumbers = 0;
+  do {
+    sumEvenNumbers += evenNumber;
+    evenNumber += 2;
+    count++;
+  } while (count < n);
+  return sumEvenNumbers;
+};
 
 console.log(evenNumbersSum(3)); // should output 6
 console.log(evenNumbersSum(0)); // should output 0
-console.log(evenNumbersSum(10)); // should output 90
+console.log(evenNumbersSum(10)); // should output 90
diff --git a/1-exercises/E-for-loop/exercise1.js b/1-exercises/E-for-loop/exercise1.js
@@ -4,11 +4,8 @@
     Change the while loop below into a for loop.
 */
 
-
 // Change the below code to use a for loop instead of a while loop.
-let i = 0;
-while(i < 26) {
-    console.log(String.fromCharCode(97 + i));
-    i++;
+for (let i = 0; i < 26; i++) {
+  console.log(String.fromCharCode(97 + i));
 }
 // The output shouldn't change.
diff --git a/1-exercises/E-for-loop/exercise2.js b/1-exercises/E-for-loop/exercise2.js
@@ -11,23 +11,27 @@
 */
 
 const WRITERS = [
-    "Virginia Woolf",
-    "Zadie Smith",
-    "Jane Austen",
-    "Bell Hooks",
-    "Yukiko Motoya"
-]
+  'Virginia Woolf',
+  'Zadie Smith',
+  'Jane Austen',
+  'Bell Hooks',
+  'Yukiko Motoya',
+];
 
 const AGES = [
-    59,
-    40,
-    41,
-    63,
-    49
+  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:
 

diff --git a/1-exercises/F-for-of-loop/exercise.js b/1-exercises/F-for-of-loop/exercise.js
@@ -1,16 +1,24 @@
+/* eslint-disable no-restricted-syntax */
 /*
-    A for-of loop is a easy and way of looping through the elements of an array, string or any other "iterable object" (think sequence of elements).    
+    A for-of loop is a easy and way of looping through the elements of an array, string or any other "iterable object" (think sequence of elements).
 */
 
 // TODO Use a for-of loop to output each of the tube stations below.
-let tubeStations = [
-    "Aldgate",
-    "Baker Street",
-    "Picadilly Circus",
-    "Oxford Street",
-    "Tottenham Court Road"
+const tubeStations = [
+  'Aldgate',
+  'Baker Street',
+  'Picadilly Circus',
+  'Oxford Street',
+  'Tottenham Court Road',
 ];
 
+for (const station of tubeStations) {
+  console.log(station);
+}
 
 // TODO Use a for-of loop to capitalise and output each letter in the string seperately.
-let str = "codeyourfuture";
+const str = 'codeyourfuture';
+
+for (const letter of str) {
+  console.log(letter.toUpperCase());
+}
diff --git a/2-mandatory/1-weather-report.js b/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.
 
@@ -11,53 +11,50 @@
         - Hint: you can call the temperatureService function from your function
 */
 
-function getTemperatureReport(cities) {
-    // TODO
-}
-
+const getTemperatureReport = (cities) => cities.map((e) => `The temperature in ${e} is ${temperatureService(e)} degrees`);
 
 /* ======= 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);
+  const 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"
-    ]);
+  const 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"
-    ]);
+  const 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([]);
+});
diff --git a/2-mandatory/2-retrying-random-numbers.js b/2-mandatory/2-retrying-random-numbers.js
@@ -5,20 +5,24 @@
 
 // This function shouldn't be changed
 function generateRandomNumber() {
-    console.log("Generating number...");
-    return Math.round(Math.random() * 100);
+  console.log('Generating number...');
+  return Math.round(Math.random() * 100);
 }
 
-function getRandomNumberGreaterThan50() {
-    // TODO - implement using a do-while loop
-}
+const getRandomNumberGreaterThan50 = () => {
+  let number = 0;
+  do {
+    number = generateRandomNumber();
+  } while (number <= 50);
+  return number;
+};
 
 /* ======= TESTS - DO NOT MODIFY ===== */
 
-test("Returned value should always be greater than 50", () => {
-    expect(getRandomNumberGreaterThan50()).toBeGreaterThan(50);
-    expect(getRandomNumberGreaterThan50()).toBeGreaterThan(50);
-    expect(getRandomNumberGreaterThan50()).toBeGreaterThan(50);
-    expect(getRandomNumberGreaterThan50()).toBeGreaterThan(50);
-    expect(getRandomNumberGreaterThan50()).toBeGreaterThan(50);
+test('Returned value should always be greater than 50', () => {
+  expect(getRandomNumberGreaterThan50()).toBeGreaterThan(50);
+  expect(getRandomNumberGreaterThan50()).toBeGreaterThan(50);
+  expect(getRandomNumberGreaterThan50()).toBeGreaterThan(50);
+  expect(getRandomNumberGreaterThan50()).toBeGreaterThan(50);
+  expect(getRandomNumberGreaterThan50()).toBeGreaterThan(50);
 });