Masa exam: nodejs : Take 2

Part I: Theory

Please, do NOT use online resources as an assistance for this part of the exam

Section A: Please, select the correct answer or the most close to the correct one => 20 points:

1. What is Repro steps? => 2 points

• Logical steps for planning the structure of DB repository
• Steps that are required in order to reproduce a bug in the system
• Sequence of actions required to build a new nodejs server
• A process of creation of a new Github repository

2. What is the role of a helper in nodejs server architecture? => 2 points

• Get the request from the router, treat the request parameters, prepare the response of the server to the consumer
• Keep state of a specific logic portion of the system, provide processing of the data passed from the different controllers, parse the data and returned the processed response
• To be the first element in the system that should service the consumer for his CRUD request to the server
• To provide services to the system that do not require a state but should be used across the whole system

3. What is a foreign key? => 2 points

• A key by which the JWT token is signed
• A pair security key for a private key. This key is stored in online repository for asymmetric encryption processing
• A way to link between 2 tables in the relational DB
• Such a term does not exist

4. What is the code of a request redirection in HTTP protocol? => 2 points

• 2xx
• 3xx
• 4xx
• 5xx

5. What is a Jira ticket? => 2 points

• A definition of a task that should be done or details of a bug opened in the system
• A ticket by which the symmtric authentication is being processed. This key is tored in the operating system
• A portion of data used to authenticate against a nodejs server
• A synonym for a JWT token

6. Which npm package willl you use to get numerous help methods for arrays? (more than a single answer can be selected) => 2 points

• Underscore
• Nodemon
• Lodash
• All answers are correct

7. What is needed for enhancement of a security level of a JWT token? => 2 points

• Password
• Encryption
• A private key
• Secret

8. What is dotenv? => 2 points

• An environment of an operational system like release, production, etc.
• An npm package that provides the ability to set different system parameters for different system environments
• A library of .Net nodejs environment
• An npm package that is added by default while creating a new nodejs server

9. How will you ensure a specific value in a DB column that is not the IDENTITY column will not be duplicate? (more than a single answer can be selected) => 2 points

• Add another private key on this column
• Add a UNIQUE CONSTRAINT to this column
• Add a UNIQUE INDEX to this column
• I will add a method on my server to ensure no duplicates are recorded in the DB for this column

10. What is a log level => 2 points

• Log level is a level at which and up log messages will be recorded in any log target
• It's a level of details to which a design of a task should be aligned
• A level of DB logs storage to provide log shipping for a better system performance
• There is no correct answer

Section B: Please, explain the following terms the best way you can => 22 points

11. Constructor => 4 points

12. Connection string => 4 points

13. IDENTITY & SEED => 5 points

14. Abstract class => 5 points

15. Export keyword in nodejs code => 4 points

Part II: Practice on paper => 45 points

No restrictions on online resources usage. You also may use your development machine for assistance in debugging if needed.

16. You received a bug stating the following: "Intermittemtly this method results in an exception in the command line reporting of a Null reference." You're required to find and fix the problem in this method: => 10 points

    public static addWeeks(date: Date, value: number): Date {
        date.setDate(date.getDate() + (value * 7));
        return date;
    }
    

17. Having the following DB tables diagram: => 10 points

You need to write a query that returns for each user a full data. Consider that not every user in the system has an employee record. In such a case out put "Not an employee". Create By column should include the full name of the user that created the record of this an output user:

Full name	Created By	Position
John Doe	Mark Smith	Manager
Mary Smith	Klark Smith	Cashier
Patrice Raymond	Mark Smith	Not an eployee

18. Write a method in JS/TS that gets as an argument 2 dates and returns a boolean value of whether those dates share the same month. => 5 points

19. Explain the following piece of code: => 5 points

    public static dictionaryToArrayOfObjects<T>(input: _.Dictionary<T>): T[] {
        return _.map(Object.getOwnPropertyNames(input), (key: string) => input[key]);
    }
    

20. Fix the following code and fill the required gaps in it by the coding standards. The purpose of this code is to verify the user is a member of a specific role and in case the user is, a true return value should be returned by the isUserPermitted() method, otherwise false. Treat the comments as actual code written that should not be changed. => 15 points

    interface user {
    	id: number;
    	firstName: string;
    	lastName: string;
    	roles: role;
    }
    
    interface dbUser {
    	id: number;
    	first_name: string;
    	last_name: string;
    	role_id: number;
    	role_title
    }
    
    interface role {
    	id: number;
    	title: string;
    }
    
    enum Role {
    	Administrator = 1,
    	RegularUser
    }
    
    public isUserPermitted(userId: number, roles: Role[]): Promise<bool> {
    	return new Promise<bool>((resolve, reject) => {
    		Promise.all([
    			this.getUser(userId),
    		])
    		.then((user: user) => {
    			resolve(user.roles.indexOf(roles[0]) > -1);
    		});
    	});
    }
    
    private getUser(userId: number): Promise<user> {
    	return new Promise<user>((resolve, reject) => {
    		// Access to the DB that returns the user data by id as dbUser or null
    	});
    }
    

Part III: Practice on dev machine => 33 points

No restrictions on online resources usage

• Clone the repository: https://github.com/lentyaishe/masa-exam-2;
• Switch to broken-server branch;
• Create a new git repository under your personal Github called masa-exam-2;
• Load the main branch of your new repository with the contents of the broken-server branch;
• Each bug in the list should be solved in designated branch.

The following is the list of currently existing problems with the system. :

21. The server solution cannot be compiled. Fix all compilation issues accordingly. => 10 points

22. An attempt to start the server fails reporting "RangeError [ERR_SOCKET_BAD_PORT]: options.port should be >= 0 and < 65536. Received NaN". => 8 points

23. A request to an endpoint GET serverUrl:port/user/-1 crashes the server with "ECONNRESET" error. => 5 points

24. Add the needed code in order to return a collection of teachers with the current teacher interface". => 10 points

Good luck!!