对象访问器 getter和setter
var person = {
firstName: "Bill",
lastName: "Gates",
language: "en",
get lang() { // 自动解析为 lang: return this.language
return this.language;
},
set lang(value) {
this.language = value;
}
};
console.log(person.lang); // => "en"
person.lang = "chinese";
console.log(person); // => {firstName: "Bill", lastName: "Gates", language: "chinese"}
console.log(person.lang); // => "chinese"
例子1
var person = {
firstName: "Bill",
lastName: "Gates",
fullName: function() {
return this.firstName + " " + this.lastName;
}
};
console.log(person.fullName()); // => Bill Gates 以方法的形式访问
例子2
var person = {
firstName: "Bill",
lastName: "Gates",
get fullName() { // 自动解析为 fullName: "Bill Gates"
return this.firstName + " " + this.lastName;
}
};
console.log(person); // => {firstName: "Bill", fullName: "Bill Gates", lastName: "Gates"}
console.log(person.fullName); // => Bill Gates 以属性形式访问, 提供了更简洁的语法。
模拟js操作客户端的cookie
let doc = {
arp_scroll_position: 414,
PHPSESSID: "65trladb2tjqbikl0fn93akkbu",
get cookie() {
let str = "";
for (let key in this) {
if (key !== "cookie") {
str += key + "=" + this[key] + ";";
}
}
return str.slice(0, -1);
},
set cookie(value) {
let arr = value.split(";");
for (let item of arr) {
let [a, b] = item.split("=");
this[a] = b;
}
}
};
doc.cookie = `app-installed=1; expires=${new Date(
2020,
11,
11
).toGMTString()}`;
console.log(doc); // => {" expires": "Thu, 10 Dec 2020 16:00:00 GMT", PHPSESSID: "65trladb2tjqbikl0fn93akkbu", app-installed: "1", arp_scroll_position: 414, cookie: "arp_scroll_position=414;PHPSESSID=65trladb2tjqbikl0fn93akkbu;app-installed=1; expires=Thu, 10 Dec 2020 16:00:00 GMT"}
console.log(doc.cookie); // => arp_scroll_position=414;PHPSESSID=65trladb2tjqbikl0fn93akkbu;app-installed=1; expires=Thu, 10 Dec 2020 16:00:00 GMT
