Detailed explanation of access methods of JavaScript class attributes_Basic knowledge

Access methods of JavaScript class attributes

Copy code The code is as follows:

var fish = {
head : 1,
tail : 1,
feature : {
speak : false,
swim : true
}
}

One , dot operator:

Copy code The code is as follows:

console.log(fish.head );//1
console.log(fish.tail);//1
console.log(fish.feature);//Object { head:1, tail:1, feature: Object}

Second, [] operator:

Copy code The code is as follows:

console.log(fish['head']);//1

One thing to note at this time is: the attribute name must be in the form of a string
such as:

Copy code The code is as follows:

console.log(fish[head]);//Error!

So, is the following code correct?

Copy code The code is as follows:

for(var prop in fish) {
console .log(fish[prop]);
}

The answer is yes, this is because when traversing the object properties, they exist in string type, that is, the props are 'head', 'tail','feature'.