250+ JS Resources to Master Programming 💥 Cheat Sheet

Source - Datatypes In JavaScript - c-sharpcorner.com

Data Types:

//string
let string = 'ASCII text';
//int
let integer = 123456789;
//float
let float = 123.456;
//boolean, can be true or false
let t = true;
let f = false;
//undefined
let undef;//defaults to undefined
let undef = undefined;//not common, use null
//null
let nul = null;
//array
let arr = ['Hello','my','name','is','Dr.Hippo',123,null];
//object
let person = {'name':'John Smith','age':27};
//function
let fun = function(){
    return 42;
}

Operators

Basic Operators

+ — Addition
- — Subtraction
* — Multiplication
/ — Division
(...) — Grouping operator, operations within brackets are executed earlier than those outside
% — Modulus (remainder )
++ — Increment numbers
-- — Decrement numbers

JS: The useful trick that allows you to change text on hover

DevLorenzo ・ Feb 4 ・ 2 min read

#html #javascript #webdev #tutorial

Comparison Operators

== Equal to
=== Equal value and equal type
!= Not equal
!== Not equal value or not equal type
> Greater than
< Less than
>= Greater than or equal to
<= Less than or equal to
? Ternary operator

Logical Operators

&& Logical and
|| Logical or
! Logical not

Bitwise Operators

& AND statement
| OR statement
~ NOT
^ XOR
<< Left shift
>> Right shift
>>> Zero fill right shift

Loops

for - loops through a block of code a number of times.

for (statement 1; statement 2; statement 3) {
  // Coooode
}

for/in - loops through the properties of an object.
for/of - loops through the values of an iterable object.

while - loops through a block of code while a specified condition is true.

let i=0;
while (i < 10) {
    console.log(i);
    i++;
}

Break and Continue

When you use break without a label, it terminates the innermost enclosing while, do-while, for, or switch immediately and transfers control to the following statement.
When you use break with a label, it terminates the specified labeled statement.

When you use continue without a label, it terminates the current iteration of the innermost enclosing while, do-while, or for statement and continues execution of the loop with the next iteration. In contrast to the break statement, continue does not terminate the execution of the loop entirely. In a while loop, it jumps back to the condition. In a for loop, it jumps to the increment-expression.
When you use continue with a label, it applies to the looping statement identified with that label.

Source - Loops and iteration - MDN

JS: Make things happen OnScroll and create better interactive websites

DevLorenzo ・ Feb 7 ・ 1 min read

dev.to Article - 10 JavaScript string methods you should know - by @frugencefidel

Strings

Escape characters

\' — Single quote
\" — Double quote
\\ — Backslash
\b — Backspace
\f — Form feed
\n — New line
\r — Carriage return
\t — Horizontal tabulator
\v — Vertical tabulator

Array and array methods

Top 10 JavaScript Array Methods You Should Know - By Rachel Cole at morioh.com

concat(arr1,[...]) // Joins two or more arrays, and returns a copy of the joined arrays
copyWithin(target,[start],[end]) // Copies array elements within the array, to and from specified positions
entries() // Returns a key/value pair Array Iteration Object
every(function(currentval,[index],[arr]),[thisVal]) // Checks if every element in an array pass a test
fill(val,[start],[end]) // Fill the elements in an array with a static value
filter(function(currentval,[index],[arr]),[thisVal]) // Creates a new array with every element in an array that pass a test
find(function(currentval,[index],[arr]),[thisVal]) // Returns the value of the first element in an array that pass a test
findIndex(function(currentval,[index],[arr]),[thisVal]) // Returns the index of the first element in an array that pass a test
forEach(function(currentval,[index],[arr]),[thisVal]) // Calls a function for each array element
from(obj,[mapFunc],[thisVal]) // Creates an array from an object
includes(element,[start]) // Check if an array contains the specified element
indexOf(element,[start]) // Search the array for an element and returns its position
isArray(obj) // Checks whether an object is an array
join([seperator]) // Joins all elements of an array into a string
keys() // Returns a Array Iteration Object, containing the keys of the original array
lastIndexOf(element,[start]) // Search the array for an element, starting at the end, and returns its position
map(function(currentval,[index],[arr]),[thisVal]) // Creates a new array with the result of calling a function for each array element
pop() // Removes the last element of an array, and returns that element
push(item1,[...]) // Adds new elements to the end of an array, and returns the new length
reduce(function(total,currentval,[index],[arr]),[initVal]) // Reduce the values of an array to a single value (going left-to-right)
reduceRight(function(total,currentval,[index],[arr]),[initVal]) // Reduce the values of an array to a single value (going right-to-left)
reverse() // Reverses the order of the elements in an array
shift() // Removes the first element of an array, and returns that element
slice([start],[end]) // Selects a part of an array, and returns the new array
some(function(currentval,[index],[arr]),[thisVal]) // Checks if any of the elements in an array pass a test
sort([compareFunc]) // Sorts the elements of an array
splice(index,[quantity],[item1,...]) // Adds/Removes elements from an array
toString() // Converts an array to a string, and returns the result
unshift(item1,...) // Adds new elements to the beginning of an array, and returns the new length
valueOf() // Returns the primitive value of an array

Functions

Syntax

function name(parameter1, parameter2, parameter3) {
  // code to be executed
}

Examples

function myFunction(p1, p2) {
  return p1 * p2;   // The function returns the product of p1 and p2
}

let x = myFunction(4, 3);   // Function is called, return value will end up in x

function myFunction(a, b) {
  return a * b;             // Function returns the product of a and b
}

// Convert Fahrenheit to Celsius:
function toCelsius(fahrenheit) {
  return (5/9) * (fahrenheit-32);
}
document.getElementById("demo").innerHTML = toCelsius(77);

Source - JavaScript Functions - w3schools

Maths

Methods

Finally - How to understand math - Awesome resource list 🚀

DevLorenzo ・ Mar 30 ・ 2 min read

#productivity #webdev #beginners #javascript

Properties

E — Euler’s number
LN2 — The natural logarithm of 2
LN10 — Natural logarithm of 10
LOG2E — Base 2 logarithm of E
LOG10E — Base 10 logarithm of E
PI — The number PI
SQRT1_2 — Square root of 1/2
SQRT2 — The square root of 2

Date

JS: How to get current date and make your sites more up to date

DevLorenzo ・ Feb 12 ・ 3 min read

Javascript date objects allow us to work with date and time. We can retrieve information for it by creating a date and assign and assigning it to a variable:

let d = new Date(); // We usually call it d or date

Date object provide us a lot of different methods, the most used are year, month, day, hours, minutes, seconds, and milliseconds. Remember that you always have to precise the entire year (1950 and not only 50), that we always start with 0 (so, for example, December is the eleventh, a minute is composed of 59 seconds...) and that day is in a 24 hours format.

You can then retrieve from date a lot of differents info:

d.getDate() Returns the day of the month (from 1-31)
d.getDay()  Returns the day of the week (from 0-6)
d.getFullYear() Returns the year
d.getHours()    Returns the hour (from 0-23)
d.getMilliseconds() Returns the milliseconds (from 0-999)
d.getMinutes()  Returns the minutes (from 0-59)
d.getMonth()    Returns the month (from 0-11)
d.getSeconds()  Returns the seconds (from 0-59)

We can also set things... Open the article to continue reading

Events

Mouse

onclick - The event occurs when the user clicks on an element
oncontextmenu - User right-clicks on an element to open a context menu
ondblclick - The user double-clicks on an element
onmousedown - User presses a mouse button over an element
onmouseenter - The pointer moves onto an element
onmouseleave - Pointer moves out of an element
onmousemove - The pointer is moving while it is over an element
onmouseover - When the pointer is moved onto an element or one of its children
onmouseout - User moves the mouse pointer out of an element or one of its children
onmouseup - The user releases a mouse button while over an element

Keyboard

onkeydown - When the user is pressing a key down
onkeypress - The moment the user starts pressing a key
onkeyup - The user releases a key

Frame

onabort - The loading of a media is aborted
onbeforeunload - Event occurs before the document is about to be unloaded
onerror - An error occurs while loading an external file
onhashchange - There have been changes to the anchor part of a URL
onload - When an object has loaded
onpagehide - The user navigates away from a webpage
onpageshow - When the user navigates to a webpage
onresize - The document view is resized
onscroll - An element’s scrollbar is being scrolled
onunload - Event occurs when a page has unloaded

Form

onblur - When an element loses focus
onchange - The content of a form element changes (for , and )
onfocus - An element gets focus
onfocusin - When an element is about to get focus
onfocusout - The element is about to lose focus
oninput - User input on an element
oninvalid - An element is invalid
onreset - A form is reset
onsearch - The user writes something in a search field (for )
onselect - The user selects some text (for and )
onsubmit - A form is submitted

Drag

ondrag - An element is dragged
ondragend - The user has finished dragging the element
ondragenter - The dragged element enters a drop target
ondragleave - A dragged element leaves the drop target
ondragover - The dragged element is on top of the drop target
ondragstart - User starts to drag an element
ondrop - Dragged element is dropped on the drop target

Clipboard

oncopy - User copies the content of an element
oncut - The user cuts an element’s content
onpaste - A user pastes content in an element

Media

onabort - Media loading is aborted
oncanplay - The browser can start playing media (e.g. a file has buffered enough)
oncanplaythrough - When browser can play through media without stopping
ondurationchange - The duration of the media changes
onended - The media has reached its end
onerror - Happens when an error occurs while loading an external file
onloadeddata - Media data is loaded
onloadedmetadata - Meta Metadata (like dimensions and duration) are loaded
onloadstart - Browser starts looking for specified media
onpause - Media is paused either by the user or automatically
onplay - The media has been started or is no longer paused
onplaying - Media is playing after having been paused or stopped for buffering
onprogress - Browser is in the process of downloading the media
onratechange - The playing speed of the media changes
onseeked - User is finished moving/skipping to a new position in the media
onseeking - The user starts moving/skipping
installed - The browser is trying to load the media but it is not available
onsuspend - Browser is intentionally not loading media
ontimeupdate - The playing position has changed (e.g. because of fast forward)
onvolumechange - Media volume has changed (including mute)
onwaiting - Media paused but expected to resume (for example, buffering)
animationend - A CSS animation is complete
animationiteration - CSS animation is repeated
animationstart - CSS animation has started

Other

transitionend - Fired when a CSS transition has completed
onmessage - A message is received through the event source
onoffline - Browser starts to work offline
ononline - The browser starts to work online
onpopstate - When the window’s history changes
onshow - A element is shown as a context menu
onstorage - A Web Storage area is updated
ontoggle - The user opens or closes the element
onwheel - Mouse wheel rolls up or down over an element
ontouchcancel - Screen touch is interrupted
ontouchend - User finger is removed from a touch screen
ontouchmove - A finger is dragged across the screen
ontouchstart - Finger is placed on touch screen

Asynchronous JS and Error handling

Asynchronous JS: Finally discover how to use SetTimeout and SetInterval

DevLorenzo ・ Feb 7 ・ 2 min read

SetTimeout will wait foo seconds and then execute the action. SetInterval will execute this same action every foo seconds.
Both can be inline or multiline, I recommend using multiline 99% of the time. It's important to notice that they work in milliseconds.

SetTimeout:

setTimeout(function(){
    alert("Hello World!"); 
}, 2000); // 2 seconds 

setTimeout(function(){ alert("The fifth episode of the series"); }, 3000);

SetInterval:

setInterval(function() {
  alert("I want to show you another Javascript trick:");
}, 1000); 

setInterval(function() {alert("How to work with SetTimeout and SetInterval");}, 1000);

If you want to remove the first delay you have to add code a first time out of the function. I recommend you save this code in a separate function you can call whenever you need. Continue reading here

Asynchronous JS: Finally discover how to use SetTimeout and SetInterval

DevLorenzo ・ Feb 7 ・ 2 min read

#javascript #webdev #programming #beginners

First, it's important to notice that a majority of backend actions have an unknown result, we don't know if it will work when we write our code. So we always have to write two different codes, one if the action works, another if the action results in an error. This is exactly how a try/catch work, we submit a code to try, if it works code continues, if it doesn't we catch the error (avoiding the app crashing) and run another code. This is a very common thing we don't only use in web development (also in Android app development with java for example).

Try / Catch

  try {
  // Try to run this code 
 // For example make a request to the server
}
catch(e) {
  console.log(e)
  // if any error, Code throws the error
 // For example display an error message to the user
}

Promises

The big problem with try/catch is that when you have to nest it (and you will have), it's really messy and difficult to read and write. So Javascript support promises with async functions:

Syntax: new Promise (executor)
executor= (accept, reject) =>{}

var asyncronus_function = (number)=>
        {
            return new Promise( (accept, reject)=>
            {
            })
        }

This function returns a promise object.
If function end well we return a accept(), otherwise reject()
More here

Projects ideas to become a javascript master

Projects ideas to become a javascript master 🚀 Resource compilation 💥 + Giveaway⚡

DevLorenzo ・ Apr 10 ・ 7 min read

a) General (for beginners)

Converters
Word Counter
Timer / Clock
Random password generator
Calculator

b) Games

Guess the number
Math time!
Other Games

c) Social & Websites

Log-in, Sign-up
Filter
To-Do List
Social
Portfolio

Open the post for more info about each project!

Other resources:

Table of content

My cheat Sheet
Projects ideas to become a javascript master
Other resources
1. Complete Javascript cheat sheets
2. JS promises
3. JS Arrays
4. JS loops
5. Preprocessor
6. CoffeScript
7. EJS
8. Babel
9. JS Frameworks & Libraries
10. Angular
11. Vue
12. React
13. JQuery
14. Others
15. Node

Complete JS cheat sheets:

By HTML cheat sheet.com - Interactive

Incredible resource --> By website setup

PDF Version

Two Others:
By overapi

JS promises (Asynchronous JS):

Dev.to article

Asynchronous JS: Working with try/catch and promises

DevLorenzo ・ Feb 12 ・ 2 min read

Quick reference - By autotelicum - PDF Version

Dev.to article

Asynchronous JS: Finally discover how to use SetTimeout and SetInterval

JS preprocessor:

CoffeeScript:

CoffeeScript website

Others:
At karloeaspirity.io

JS to CoffeeScript

EJS:

Babel:

JavaScript-based Frameworks & Libraries:

Article Angular vs vue vs react at codeinwp.com

Best Javascript Frameworks - article at hackr.io

Angular

By angular.io

Vue

By vue mastery

Other - By marozed

React

At GitHub: React + Typescript cheat sheet

Others:
By react cheat sheet.com

JQuery

AJAX intro + cheat sheet at GitHub

By ascarotero.com - Really well done

By Website Setup - PDF Version

By make website hub

PDF Version

Article about top 10 jquery cheat sheets

Or by over API

Others

Ember.js:

Meteor:

Mithril:

Node