享元模式以共享的形式高效地支持大量细粒度对象的重用。
享元模式主要用于减少创建对象的数量，以减少内存占用和提高性能。
一般将享元类中的内部状态进行处理变成享元类的成员变量，而外部状态通过注入的方式进行处理。
它和单例模式的区别是单例模式只有一个对象一个实例，而享元模式有n个实例。享元模式主要是为了节约内存空间提升性能，而单例模式主要是为了共享状态。
const student = function(id, name, age, grade, phone) {
this.id = id;
this.name = name;
this.age = age;
this.grade = grade;
this.phone = phone;
this.getInfo = function() {
return `${this.id}${this.name}${this.age}${this.phone}`
}
};
const studentInfo = function() {
this.create = function(id, name, age, grade, phone) {
let s = studentFactory(id, name);
s.age = age;
s.grade = grade;
s.phone = phone;
return s;
}
};
const studentFactory = (function() {
let s = {};
return function(id, name) {
if (s[id + name]) {
console.log("调用已有对象");
return s[id + name];
} else {
const newStudent = new student(id, name)
s[id + name] = newStudent;
console.log("新建对象");
return newStudent;
}
}
})();
let s = new studentInfo();
let list = [];
for (let i = 0; i < 100; i++) {
list.push(s.create("1", "shada", "18", "1", "123"));
}
console.log(list[0]);
console.log(list[0].getInfo());
