Node.js

Question 1

What is Node.js?

Answer 1

Node is a program that allows JavaScript to run outside of the web browser.

Question 2

What can Node.js be used for?

Answer 2

Node can be used to build back end web apps, command line programs.

Question 3

What is a REPL?

Answer 3

Read Eval Print Loop

Question 4

What is a computer process?

Answer 4

The instance of a computer program that is being executed by one or many threads.

Question 5

Why should a full stack Web developer know that computer processes exist?

Answer 5

Full stack development depends on many processes working together to form an app. So understanding what these processes are doing or at least are running is important.

Question 6

What is the process object in a Node.js program?

Answer 6

It is a global object that has information and control over the current node process.

Question 7

How do you access the process object in a Node.js program?

Answer 7

Since it’s a global object, you can access it simply by typing process.

Question 8

What is the data type of process.argv in Node.js?

Answer 8

The data type is an array.

Question 9

What is a JavaScript module?

Answer 9

A single js file. Each file is a small part of many other modules that come together to be a program.

Question 10

What values are passed into a Node.js module’s local scope?

Answer 10

__dirname, __filename, exports, module, require.

Question 11

Give two examples of truly global variables in a Node.js program.

Answer 11

global and process

Question 12

What is the purpose of module.exports in a Node.js module?

Answer 12

So that module file knows it is going to be allowing other modules to pair/group up with it.

Question 13

How do you import functionality into a Node.js module from another Node.js module?

Answer 13

The require method is used in the module that wants to use a functionality thats from another module.

Question 14

What is the JavaScript Event Loop?

Answer 14

The event loop is how the JavaScript runtime pushes asynchronous callbacks onto the stack once the stack is cleared.

Question 15

What is different between “blocking” and “non-blocking” with respect to how code is executed?

Answer 15

.

Question 16

What is a directory?

Answer 16

It is a file that holds all other files.

Question 17

What is a relative file path?

Answer 17

A relative file path doesn’t have the forward slash.

Question 18

What is an absolute file path?

Answer 18

An absolute file path starts with the forward slash /

Question 19

What module does Node.js include for manipulating the file system?

Answer 19

fs

Question 20

What method is available in the Node.js fs module for writing data to a file?

Answer 20

fs.writeFile

Question 21

Are file operations using the fs module synchronous or asynchronous?

Answer 21

Both depending on which operation is being used.

Question 22

What is NPM?

Answer 22

NPM allows users to share their js code to others.

Question 23

What is a package?

Answer 23

A package contains modules that are often small. The package contains a small building block to solve a problem.

Question 24

How can you create a package.json with npm?

Answer 24

By being in the root directory and then using the command “npm init –yes”

Question 25

What is a dependency and how to you add one to a package?

Answer 25

Packages that are required by your application in production. Use “npm install (name of package) “

Question 26

What happens when you add a dependency to a package with npm?

Answer 26

Your package.json gets updated with the dependency you just installed.

Question 27

How do you add express to your package dependencies?

Answer 27

npm install express

Question 28

What Express application method starts the server and binds it to a network PORT?

Answer 28

The listen() method on the variable that holds the express function.

Question 29

How do you mount a middleware with an Express application?

Answer 29

By using the use method on the Express application.

Question 30

Which objects does an Express application pass to your middleware to manage the request/response lifecycle of the server?

Answer 30

A callback function to run a block of code everytime there is a req and res.

Question 31

What is the appropriate Content-Type header for HTTP messages that contain JSON in their bodies?

Answer 31

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Question 32

What does the express.json() middleware do and when would you need it?

Answer 32

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Question 33

What is the significance of an HTTP request’s method?

Answer 33

It allows the user to properly access the server. If the request method didn’t have the proper functionality, it would be extremely problematic.

Question 34

What does express.static() return?

Answer 34

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Question 35

What is the local __dirname variable in a Node.js module?

Answer 35

.

Question 36

What does the join() method of Node’s path module do?

Answer 36

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