js 函数调用模式

function sayHello() {
    console.log("Hello!");
}

sayHello(); // 输出: Hello!

var person = {
    firstName: "John",
    lastName: "Doe",
    getFullName: function() {
        return this.firstName + " " + this.lastName;
    }
};

console.log(person.getFullName()); // 输出: John Doe

function Person(firstName, lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
    this.getFullName = function() {
        return this.firstName + " " + this.lastName;
    };
}

var john = new Person("John", "Doe");
console.log(john.getFullName()); // 输出: John Doe

function sum(num1, num2) {
    return num1 + num2;
}

var result = sum.apply(null, [1, 2]); // 输出: 3

function greet(greeting, punctuation) {
    return greeting + ", " + this.name + punctuation;
}

var person = { name: "John" };
console.log(greet.call(person, "Hello", "!")); // 输出: Hello, John!

var person = {
    firstName: "John",
    lastName: "Doe",
    getFullName: function() {
        return this.firstName + " " + this.lastName;
    }
};

var fullName = person.getFullName.bind(person);
console.log(fullName()); // 输出: John Doe