js 判断对象是否为空

• 1、JSON.stringify()

const obj = {}
const bool = JSON.stringify(obj) === "{}"
console.log(bool)

• 2、for in遍历

const obj = {}
let bool
for (var k in obj) {
	bool = k ? false : true
}

• 3、Object.keys()

const obj = {}
let bool
bool = Object.keys(obj).length ? false : true

4、Object.getOwnPropertyNames()

const obj = {}
let bool
bool = Object.getOwnPropertyNames(obj).length ? false : true