Study for Interview

Question 1

What are the parts of a url?

Answer 1

protocol: domain name/parameters ? queries

Question 2

What is the DOM?

Answer 2

Document-Object-Model, a copy of the code from the server that can be manipulated with javascript

Question 3

What are the typical parts of a server js file?

Answer 3

• import external resources (i.e. Express)
• api end points (app.get)
• app listen with the port settings (app.listen)

Question 4

Is Node primarily a sync or async programing language?

Answer 4

Async - it’s built on callbacks

Question 5

How many threads does node have?

Answer 5

1 thread (thread = an operation that is happening in the same time with another one)

Question 6

What are the projects suitable for node?

Answer 6

Single thread websites with simple NoSQL DBs and API support

Question 7

What is the difference between a SQL and NoSQL database?

Answer 7

SQL is a relational data model (all data is structured the same, vertically scalable)
NoSQL is a document data model (data can be structured differently, horizontally scalable)

Question 8

What are the three definitions of Mongoose?

Answer 8

1. A middleware connecting the Controller with the Model
2. “validation” layer (validates data between the controller and the model)
3. Object Document Mapper (maps the connection between the Documents inside the DB with the Objects in the controller)

Question 9

What is a callback function?

Answer 9

A callback is function which is sent as a parameter to another function in order to be used after the initial function runs
- example:
$("#btn_1").click(function() {
	  alert("Btn 1 Clicked");
	});

Question 10

What is a closure function?

Answer 10

A closure is an inner function that has access to the outer (enclosing) function’s variables and the global variables

Question 11

What is a recursive function?

Answer 11

• Recursive functions iterate over an operation repeatedly until it arrives at a result
• Example:
  var factorial = function(number) {
  if (number <= 0) { // terminal case
  return 1;
  } else { // block to execute
  return (number * factorial(number - 1));
  }
  };
  console.log(factorial(6));

Question 12

What are RESTful web services?

Answer 12

• Representational State Transfers

Clients can make requests that elicits a response in HTML, XML or JSON format

Question 13

Difference between PUT and PATCH?

Answer 13

PUT is used to update a resource and PATCH is used to modify it

Question 14

What are common CRUD operations?

Answer 14

GET, POST, PUT, PATCH, DELETE

Question 15

What are CRUD operations?

Answer 15

Create, Read, Update and Delete - requests made to the server in order to get a response.

Question 16

What does MCV stand for?

Answer 16

Model (database), Controller (server), View (client)

Question 17

What are the most common npm apps being used?

Answer 17

express, mocha, chai, morgan, faker, bcryptjs, body-parser, mongo, mongoose

Question 18

Describe the HTTP requests/response life cycle.

Answer 18

Client sends a request - request method and path are used to route to correct request handler.
Server sends a response object with status code and headers, and body if response has content

Question 19

Describe the architecture of a basic Express app. How is it organized?

Answer 19

• a way to listen for HTTP requests over a port
• a way to inspect and interact with HTTP request and response objects
• a way to route HTTP requests from clients to the right request handlers
• a way to serve static assets to client browsers (e.g., our route for /)
• a way to serve data to clients

Question 20

Describe how a Mongo database is structured

Answer 20

Mongo is made up of collections of documents.
A document is an object comprised of keys and values. Mongo accepts strings, integers, floating point decimals, booleans, null, arrays, objects, timestamps, and object ids as value types.

Question 21

What is the purpose of bcrypt in the authentication process?

Answer 21

bcrypt is an adaptive function: over time, the iteration count can be increased to make it slower, so it remains resistant to brute-force search attacks

Question 22

How do JSON web tokens work?

Answer 22

JWT digitally signs tokens to prevent fraud. When the server generates the token, it generates a signature by combining the contents of the token with a secret private key using an encryption algorithm.