[ES6] Getting started

1. What is ES6

New JavaScript syntax standard

• Officially released in June 2015
• Use babel syntax converter to support low-end browsers
• Popular libraries are basically built on ES6, React and vue are developed using ES6 new syntax by default

2. What's in ES6

1. Scope
let and const
  let: the internal scope in the curly braces is valid
  const: define unmodifiable variables

2. string

• Use backticks (the one above the Tab key) to write variables directly
• Multi-line string
• Farewell + stitching string
  

3. Function extension

• Arrow function
  
• Parameter default

const add = (num1,num2=1) =>{   //num2默认值为1
	return num1+num2
}
console.log(add(3,4))   //输出7
console.log(add(3))		//输出4

• Expansion function
  

Extended object
Object extension

• Object.keys, values, entries
  Object.key
  return value: a string array representing all enumerable properties of a given object

• Object method shorthand, calculating attributes

• Spread operator (not ES6 standard, but also supported by babel)
  
  destructuring assignment
  function can also return multiple values

• Array destructuring

• Object deconstruction
  
  modularization
  ES6 comes with a modularization mechanism, say goodbye to seajs and require.js

• Import, import {}

• Export , Export default

• Node does not support it yet, you need to use require to load files

I hope it will be helpful to everyone, and wish us all to be outstanding learning champions! !