JavaScript Basics.txt

JavaScript Basics

Number(var) //converts var into type number
alert("")


Printing
----------
console.log("")


Input
--------
var name = prompt("What is your first name? ")

Types
------
Number
String
Boolean
Undefined
Null
Symbol
Object

Comparisons
------------
!== #not equal to
=== #equal to
>=  #greater than or equal to
<=  #less than or equal to
<   #less than
>   #greator than

Variables
---------
var firstName

Conditionals
-------------
if 
else
else if 

Logical Operators
------------------
&& #and
|| #or
! #not

Logical & Operator
------------------
this.state.error && <p>{this.state.error}</p> // if this.state.error has a value then render the error to the screen, otherwise never show this element

Ternary Operator
----------------
Description: props.expense ? props.expense.description : '' // if props.expense exists (true) then we will set the value of description to props.expense.description. If it does not exist (false) then we will set it to an empty string


Functions
---------
var a = function name() {} //Function Expression
function name() {} //Function Declaration (BEST WAY)
return

parameters - placeholders for future arguments
arguments - functions execute against arguments



One of the rules of thumbs for a developer is "not to repeat yourself. Ideally I should want to make things as "efficient" as possible. 

Add "arguments" to functions. This is how I make my function "extensible" and customizable.