在javascript中初始化对象时的一些问题

let obj = {};

let obj = new Object();

obj.name = "John"; // 使用点号
obj["age"] = 25; // 使用方括号
obj.sayHello = function() {
  console.log("Hello!");
};

console.log(obj.name); // 使用点号
console.log(obj["age"]); // 使用方括号
obj.sayHello(); // 调用方法

let obj = {
  sayHello: function() {
    console.log("Hello!");
  },
  sayHi: () => {
    console.log("Hi!");
  }
};

function Person(name, age) {
  this.name = name;
  this.age = age;
}

let person = new Person("John", 25);

function Person(name, age) {
  let privateVar = "I am private";

  this.name = name;
  this.age = age;

  let privateMethod = function() {
    console.log(privateVar);
  };

  this.publicMethod = function() {
    privateMethod();
  };
}

let person = new Person("John", 25);
person.publicMethod(); // 输出 "I am private"