Comments，注释

Variable

Array

Function - Reusable code

Operator

 (a=4+4) > 8// 赋值后的变量参与后面的比较

Boolean

Switch

Object

object={}  array=[]  function(){} 都是Object

JSON

Loops

Why zero-based indexing

Math

parseInt

Conditional (Ternary) Operator

(...args) Spread syntax

Destructuring assignment 解构赋值