判断对象中是否含有某元素

1. if(map[‘key’])

let test = {name : 'lei'}
if(test["name"]){
	console.log('success')
}else{
	console.log('error')
}

2. in 运算符

let test = {name : 'lei'}
if('name' in test){
	console.log('success')
}else{
	console.log('error')
}

3.hasOwnProperty()

let test = {name : 'lei'}
if(test.hasOwnProperty('name')){
	console.log('success')
}else{
	console.log('error')
}