Node.js Flashcards by Jamie Cafirma

What is a code block? What are some examples of a code block?

section of code enclosed within { }, ex: function, conditional, loop

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What is a CLI?

command-line interface, text-based

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What is a GUI?

graphical-user interface, graphical icon-based

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man

user manual for commands

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cat

combine content of files

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shows content of directory

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pwd

shows current directory

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echo

prints out text on terminal, like console.log( )

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touch

changes file timestamps, can be used to create a new file

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mkdir

creates a new directory

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renames or moves a file

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deletes a file

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copies a file

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What are the three virtues of a great programmer?

laziness, impatience, hubris

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What is Node.js?

a program that allows JS to be run outside of a web browser

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What can Node.js be used for?

it can be used for back-ends for Web applications, command-line programs anything with automation

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What is a REPL?

read-eval-print loop

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When was Node.js created?

May 27, 2009

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What is a computer process?

a process is the instance of a computer program that is being executed by one or many threads

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Roughly how many computer processes are running on your host operating system (Task Manager or Activity Monitor)?

480 processes

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

Full stack Web development is based on making multiple processes work together to form one application, so having at least a cursory awareness of computer processes is necessary

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

a global that provides info about, and control over, the current Node.js process

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

with or without require( )

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

an array of strings of the command-line arguments

What is a JavaScript module?

a single .js file

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

module, exports, require( ), __dirname, __filename

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

process, global

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

allows you to export functions and objects from a module to be used in another

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

require( relative path to file)

What is the JavaScript Event Loop?

the event loop looks at the call stack and the task queue; if the stack is empty, the event loop pushes the first thing on the queue into the stack

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

blocking means the code is occupying the call stack, non-blocking means the code is a Web API (network, DOM, events) and is pushed to the task queue

What is a directory?

a collection of files

What is a relative file path?

points to a file within the context of the current directory

What is an absolute file path?

points to a file from the root directory

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

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

.writeFile( )

Are file operations using the fs module synchronous or asynchronous?

both

What is NPM?

website, CLI, registry that provides a way to reuse code from other developers, to share your code with them, and manage different versions of code

What is a package?

a directory containing a program described by a package.json file, and a package.json file

How can you create a package.json with npm?

npm init --yes

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

another package a package needs in order to work, npm install

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

package.json will be updated to include the dependency and the package for the dependency will be installed to the node_modules directory

How do you add express to your package dependencies?

npm install express

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

app.listen( )

How do you mount a middleware with an Express application?

app.use( )

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

req and res

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

application/json

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

returns a middleware function that parses JSON, attaches data to the body property of the req object, used when expecting requests with JSON

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

describes the action the server has to perform

What does express.static( ) return?

middleware function that serves files within a given root directory

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

absolute file path of directory of current module

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

join all given path segments