Node Flashcards
What is Node.js?
Node.js is a program that allows JavaScript to be run outside of a web browser. It is commonly used to build back ends for Web applications, command-line programs, or any kind of automation that developers wish to perform. Node.js is powered by V8; the same JavaScript engine in the Google Chrome browser. It is free, open-source software and its source code is available on GitHub.
What can Node.js be used for?
It is commonly used to build back ends for Web applications, command-line programs, or any kind of automation that developers wish to perform.
What is a REPL?
A read–eval–print loop (REPL), also termed an interactive toplevel or language shell, is a simple interactive computer programming environment that takes single user inputs, executes them, and returns the result to the user; a program written in a REPL environment is executed piecewise.
When was Node.js created?
May 27, 2009
What back end languages have you heard of?
C++, Python, Java, C# (.net is a framework for C#), Ruby, PHP, Go, Perl, JavaScript/Node
What is the process object in a Node.js program?
The process object is a global that provides information about, and control over, the current Node.js process. As a global, it is always available to Node.js applications without using require( ). It can also be explicitly accessed using require( ):
const process = require(‘process’);
How do you access the process object in a Node.js program?
const process = require(‘process’);
And by typing ‘process’ because it is a global variable
What is the data type of process.argv in Node.js?
An array
What is a JavaScript module?
In JavaScript, a “module” is a single .js file. Node.js supports modules using a system heavily influenced by CommonJS. Most non-trivial Node.js programs are made of many, many modules. Authors of Node.js programs strive to separate their code into modules that each provide a small chunk of functionality. The program as a whole is the result of all of these modules working together in concert.
What values are passed into a Node.js module’s local scope?
__dirname
__filename
exports
module
require
Give two examples of truly global variables in a Node.js program.
clearImmediate(immediateObject)
clearInterval(intervalObject)
clearTimeout(timeoutObject)
console
global
process
What is the purpose of module.exports in a Node.js module?
import functionality into a node.js module from another node.js module
How do you import functionality into a Node.js module from another Node.js module?
module.exports = (name of function you want to export)
require(‘./name of file you want to import’) in the receiving file
What is a directory?
An organizational structure to store files as a group. A directory is a location for storing files on your computer. Directories are found in a hierarchical file system, such as Linux, MS-DOS, OS/2, and Unix.
What is a relative file path?
A relative path refers to a location that is relative to a current directory. Relative paths make use of two special symbols, a dot (.) and a double-dot (..), which translate into the current directory and the parent directory. Double dots are used for moving up in the hierarchy.
What is an absolute file path?
An absolute path is defined as the specifying the location of a file or directory from the root directory(/). In other words we can say absolute path is a complete path from start of actual filesystem from / directory.
What module does Node.js include for manipulating the file system?
The fs (file system) module
What method is available in the Node.js fs module for writing data to a file?
fs.writeFile
Are file operations using the fs module synchronous or asynchronous?
Asynchronous - we know that they are asynchronous because they use a callback function
