Scrimba's JavaScript Deep Dive - Part I

Getting Started:

Variables & String

by default, variables have the value "undefined", meaning is empty
we can declare and assign variables at the same time
camel-cased: first letter is lowercase, but next word is uppercase (by convention). For example: firstName
Requirements: 1) name just letter, number, "$", and "_" 2) first character must not be a number, 3) cannot use reserved name (like "var")
Browser: window // Server: global
Sloppy (normal) mode: default // Strict mode: throws more errors, but prevents better -> "use strict"; But this does not solve all the problems
let& const to declare variables, but let can be reassigned (like var). Use cont unless it will be reassigned
Variable shadowing: let & const are block-scoped
Template literal for string interpolation: to add variables in strings Hi ${username} (we can do operations or put conditions inside the {} ). It use ` not '
Variables names are case sensitive
Variables names should be descriptive and in camel-cased. Any variable can be of any type, that is why is so important to follow this convention, so others know what we are doing
Other conventions: isSomething or hasSomething to do condicional, for constant we use all caps and _ to separate (FIRST_NUMBER)