You are a Software Engineer for the city of Baltimore, and you have been asked to design, test, and code the backend for an Electric Scooter Hire app system. Since the city already has front-end developers, you won’t need to design the UI, just the back-end!

In this challenge, you will be required to

1. Create the UML Diagrams for the app
2. Write tests for your Classes, including their properties and methods
3. Build the system using JavaScript Classes

npm install

To run tests in "watch" mode

npm test

To get a coverage report

npm run coverage

The company has provided you with some specs that the front end developers want for their Scooter App. You should refer back to this page as you build your UML design and code.

This class represents the individual scooters that users will rent from stations. A Scooter is either docked at a station or checked out to a User. Scooters can also be broken or need charging.

Each Scooter should have the following properties

• station: string; the station the scooter is located at or null if checked out
• user: the User who checked out the Scooter, or null if docked
• serial: a number assigned sequentially from nextSerial
• nextSerial: a static number which starts at 1 and increments each time a new serial number is assigned
• charge: a number from 0 (no charge at all) to 100 (fully charged)
• isBroken: boolean

All Scooters are docked, charged, and in good repair initially. The Scooter constructor has one parameter:

• the Station the scooter is docked at.

Your constructor must initialize all of the other properties, too.

Each Scooter should have the following methods

• rent(user)

  • If the Scooter is charged above 20% and not broken, remove it from its station, check it out to user.
  • Otherwise, throw an error scooter needs to charge or scooter needs repair.

• dock(station)

  • Return the scooter to the station. Be sure to clear out the user, so they don’t get charged unfairly!

• recharge()

  • BONUS: Set a timer to incrementally update the Scooter’s charge to 100.
  • Every so often, log the new percentage of charge.

• requestRepair()

  • BONUS: Use a setInterval timer to schedule a repair in 5 seconds.
  • When time elapses, set isBroken to false and log repair completed to the console.

NOTE: The recharge() and requaestRepair() methods require that you deliver a message after a certain interval of time. In JavaScript, to simulate waiting for a scooter to charge you can make use of the setTimeout call for example in src/Scooter.js:

async charge() {
    console.log('Starting charge');
    
    await new Promise(resolve => setTimeout(resolve, 2000)); // wait 2 seconds
    this.charge = 100

    console.log('Charge complete');   
}

The associated Jest test in tests/Scooter.test.js will look as follows:

test("charge", async () => {
    const scooter = new Scooter();
    await scooter.charge(); // we need to wait for the charge!
    expect(newScooter.charge).toBe(100);
});

When a new person downloads the app and registers, a new User object is created to store user information in the system.

In a real world scenario, this object would also store credit card information, rental history, etc.

Each User has the following properties:

• username: String
• password: String
• age: In years
• loggedIn: boolean

username, password, and age are provided to the constructor as arguments. loggedIn represents whether the user is currently logged in. A user is NOT logged in when they first register.

Each User has the following methods (each called by ScooterApp):

• login(password)
  • If password is correct, logs the User in. If not, throws incorrect password error.
• logout()
  • Logs the User out.

The ScooterApp keeps track of all registered users, plus all the scooters and their status. Many ScooterApp methods represent user actions such as logging in or returning a scooter. The ScooterApp uses properties and methods of Scooter and User objects.

Each ScooterApp should include the following properties

• stations: An object whose keys are the names of station locations, and whose values are arrays of Scooters. You can hard-code these stations in the constructor. There should be at least three. Initially, there are no scooters at any stations.
• registeredUsers: An object whose keys are usernames to store all users 

Each ScooterApp should include the following methods

• registerUser(username, password, age)
  • If the user is not already registered AND is 18 or older, then add them as a new registered user. Log to the console that the user has been registered and return the user.
  • If the user cannot be registered, throw an error: already registered or too young to register.
• loginUser(username, password)
  • Locate the registered user by name and call its login method. Log to the console that the user has been logged in.
  • If the user cannot be located or if the password is incorrect, then throw an error: Username or password is incorrect.
• logoutUser(username)
  • Locate the registered user and call its logout method. Log user is logged out to the console.
  • If the user cannot be located, throw no such user is logged in error
• createScooter(station)
  • This method is called by the Scooter company’s home office when new scooters are deployed.
  • Create a new scooter, add it to the station’s scooter list, and set its station property. Log created new scooter to the console. Return the scooter.
  • Throws no such station error if the station does not exist. 
• dockScooter(scooter, station)
  • Add the scooter to the station’s scooter list, and dock it.
  • Log scooter is docked to the console. 
  • Throws no such station error if the station does not exist.
  • Throws scooter already at station error if the scooter is already there.
• rentScooter(scooter, user)
  • Locate the given scooter at one of the stations, and remove it from that station. Rent it to the user. Log scooter is rented to the console.
  • If the scooter is already rented, throw the error scooter already rented.
• print()
  • You will use this handy method when testing your ScooterApp.
  • Log the list of registered users to the console.
  • Log the list of stations and how many scooters are at each station to the console.
  • Take a moment to format it nicely so you can read it.