Section 1
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client vs server
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Section 1
(50 cards)
client vs server
client side - sends HTTP request, renders response data server side - handles HTTP request, generates/sends response
API
Application Programming Interface is offered by a server for communication with a client app. A client computer program can send instructions to the server and get data from the server by sending requests to various URL endpoints that form the API.
http core library
how Node runs an HTTP server and supports backend applications.
the event loop
A system to sequentially process tasks. makes callbacks possible Node processes events sequentially from the event queue which is just a queue of events (function calls, etc.). If the event is asynchronous, Node asks the operating system to notify it when the event is ready for processing. Meanwhile, it continues processing other events in the queue. The thread pool is a collection of technologies that help execute events, such as accessing the file system.
URI
Uniform Resource Identifier - specifies how to access a resource on the Internet
***
URL
Uniform Resource Locator; a location or address identifying where documents can be found on the Internet; a Web address
shell
A user interface for access to an operating system's services.
HTTP core library
how Node runs an HTTP server and supports backend applications.
nodemon
nodemon watches the files in the directory it's running in, and, if any data changes will automatically restart your node application.
How do you import a module?
require();
Server-Side JavaScript
runs in Node.js process, doesn't render anything, handles http requests, sends responses, has no window of document objects, does not interface with HTML or DOM, no selector etc; can make direct HTTP resuests, uses modules to split code into files
client-side javascript
runs in a browser process, renders the page, handles user interactions, makes requests, has window and document objects, interfaces with HTML and DOM, uses AJAX to make HTTP requests, uses script tags to split code into files
node core libraries
fs, http, node modules
dotenv
a Node package that assists us with handling environment variables for our development environment. When dotenv is configured, it will look for a file called .env in the root of the application and load those variables into memory.
testing code
used to state expectations production code will meet and raises errors when stated expectations are not met. two primary reasons to write test code are 1) to ensure production code does what it's intended to do 2) to ensure that production code doesn't break with you refactor it.
Modules
A set of functions you want to include in your application a self-contained component that is intended to perform a function and be portable enough to swap in and out as needed. The module has all it needs to perform this function. independent, interchangeable pieces of code that contain everything necessary to execute one separate aspect of the desired functionality. This principle in Computer Science is called Separation of Concerns. Simply put, modules are either packages or libraries that you can import and use in your code. portable, encapsulated and reusable
Unix Philosophy
The Unix philosophy is a guideline for minimalist, modular software development. Make each program do one thing well. To do a new job, build afresh rather than complicate old programs by adding new features. Expect the output of every program to become the input to another, as yet unknown, program. Don't clutter output with extraneous information. Avoid stringently columnar or binary input formats. Don't insist on interactive input. Design and build software, even operating systems, to be tried early, ideally within weeks. Don't hesitate to throw away the clumsy parts and rebuild them. Use tools in preference to unskilled help to lighten a programming task, even if you have to detour to build the tools and expect to throw some of them out after you've finished using them.
Non-blocking
Considered asynchronous
types of functions
function declaration, function expression, shorthand, aarow, generator, new function
template literals
Template literals are string literals allowing embedded expressions. You can use multi-line strings and string interpolation features with them. They allow for both multiline strings and string interpolation. console.log(`foo bar`); // foo // bar var foo = 'bar'; console.log(`Let's meet at the ${foo}`); // Let's meet at the bar Template literals are enclosed by the back-tick (` `) (grave accent) character instead of double or single quotes. Template literals can contain placeholders. These are indicated by the dollar sign and curly braces (${expression}). The expressions in the placeholders and the text between the back-ticks (` `) get passed to a function. The default function just concatenates the parts into a single string. If there is an expression preceding the template literal (tag here), this is called a "tagged template". In that case, the tag expression (usually a function) gets called with the template literal, which you can then manipulate before outputting. To escape a back-tick in a template literal, put a backslash \ before the back-tick.
Asynchronous
or non-blocking, means your code does not wait for the current line to execute before moving on to run the next line.
callback functions
A function called after another function has finished executing. The callback function is called once a particular task has finished. When an asynchronous background operation such as reading a directory finishes executing, Node needs some way to communicate this back to the program(callback). made possible by the event loop
exports
A reference to module.exports. Any reassignment of exports will not be available outside of the module exports is a reference to module.exports and cannot reassign the object module.exports. You may use either module.exports or exports within your Node app. If you want your module to be a specific object type, use module.exports. Otherwise, use exports. Using exports is recommended unless you are planning on having your module be a specific object type.module.exports and cannot reassign the object module.exports. You may use either module.exports or exports within your Node app. If you want your module to be a specific object type, use module.exports. Otherwise, use exports. Using exports is recommended unless you are planning on having your module be a specific object type.
utf8
A Unicode-based encoding such as UTF-8 can support many languages and can accommodate pages and forms in any mixture of those languages. Its use also eliminates the need for server-side logic to individually determine the character encoding for each page served or each incoming form submission.
streams
Collections of data read as input as well as outputted.
views
complete HTML documents
What JavaScript statement do you use to export a module?
module.exports
Why is using exports recommended?
exports is recommended because it will not overwrite whatever you have assigned to module.exports because exports is a reference to module.exports and cannot reassign the actual object module.exports. exports is recommended unless you are trying to make module be a specific object type
Why is the fs core module important for Node development?
Because it allows access to the file system through code(aka programmatically)
What is the difference between readdirSync and readdir?
readdirSync is synchronous and readdir is asynchronous. The former will run without letting anything else run before it is finished, while the latter will let other things run while it's running
Synchronous
or blocking, means that your code runs in sequential order. The program waits for the line of code to finish executing before moving on to the next line of code.
partials
pieces of reusable HTML components meant to be included in our views as needed
how node unit testing works**
You can think of tests as safeguards for the applications you are building. They will run not just on your local machine, but also on the CI services so that failing builds won't get pushed to production systems. We write unit tests to see if a given module (unit) works. All the dependencies are stubbed, meaning we are providing fake dependencies for a module. Each unit test has the following structure: Test setup Calling the tested method Asserting
node is
a javascript runtime built on chrome's V8 javascript engine
commonJs modules
With client-side code, we access other libraries by including them in our HTML via a script tag. Since our server-side code doesn't use HTML files, we need another way to access and include external libraries. CommonJS was created to solve this issue, and Node has adopted it as a core library. module.exports = {library here}
What is the main difference between exports and module.exports?
exports is not returned by require() and is just a convenience variable so module authors can write less code. module.exports is the object reference that gets returned from.
HTTP
Hyper Text Transfer Protocol, is a set of rules used to transfer files from a Web server onto a browser in order to view a Web page that is on the Internet.
What is the event loop and how does it handle asynchronous requests?
The event loop is the order in which the calls get processed. Like it will take an asynchronous task from the event queue and run it, then go on to the next one or it will take a synchronous task and wait until it's notified that the task is finished to go back to the event queue
Blocking
when the execution of additional JavaScript code must wait until a previous operation finishes executing. All blocking methods execute synchronously, but not all synchronous methods are blocking.
Why are modules used?
Because they are already built in libraries without any installation.
what is npm and what does it do
Npm is the node.js package manager and we use it in the command line as a tool to install node packages
TDD
test driven development - the process of writing test before writing production code.
fs
node's built in module(short for file system) way to access the file system through code
CommonJS
With client-side code, we access other libraries by including them in our HTML via a script tag. Since our server-side code doesn't use HTML files, we need another way to access and include external libraries. CommonJS was created to solve this issue, and Node has adopted it as a core library.
CRUD
create, read, update, delete
What is the difference between sync and non-sync methods in the fs module?
Sync is synchronous or non-blocking and means that the code will run in sequential order waiting for the previous code to finish executing before moving on. Non-sync is asychronous meaning that it doesn't wait for the current line of code to finish running before executing the next line.
MVC
Model View Controller MVC pattern allows for your application to have a separation of concerns, allowing specific sections of your application to be in charge of specific functionality. Model - consists of the data structures needed to store information and the methods used to interface with the data layer of the application. View - controls everything a user sees and is handled by a view engine which takes dynamic content, replaces that content with placeholders inside of an HTML file, and then sends the final HTML to the client. Controller - handles incoming requests from the client. It will interact with the model to move data in and out of the database and the view.
pipes
A way to pass information from one process to another.
What kind of information does package.json hold?
Key value pairs that communicate to npm how a node application is structured a file that communicates to npm how your application is structured, where all your dependencies are
Section 2
(18 cards)