Yu's Github

let/const block scope

let arr = [1,2,3,4]
for (let i = 0; i < arr.length; i++) {
}
console.log(i); // error

let arr = [1,2,3,4]
for (var i = 0; i < arr.length; i++) {
}
console.log(i); // 4

Hoisting

console.log(foo);
var foo = 1;

Arrow function

Arrow function no this, cannot be constructor, no prototype

// 函数声明
function test() {}
// 函数表达式
const test = function() {}
// 箭头函数
const test = () => {}

var obj = {
	commonFn : function() {
		console.log(this);
	},
	arrowFn : () => {
		console.log(this);
	}
}

obj.commonFn();
obj.arrowFn();
VM372:3 {commonFn: ƒ, arrowFn: ƒ}
VM372:6 Window {parent: Window, opener: null, top: Window, length: 2, frames: Window, …}

Template string

let getName = () => {
    return 'test';
}
let str = `
<div>
 <h1 class = "title">${getName()}</h1>
</div>
`;
document.querySelector('body').innerHTML = str;

object

var name = 'test',
	age = 18;
var obj = {
	name: name,
	age: age,
	getName: function() {
		return this.name;
	},
	getAge: function() {
		return this.age;
	}
}

let name = 'test',
	age = 18;
let obj = {
	name,
	age,
	getName() {
		return this.name;
	},
	['get' + 'Age']() {
		return this.age;
	}
}