js data return

function add(a, b) {
    return a + b;
}

console.log(add(1, 2)); // 输出: 3

function createUser(name, age) {
    return {
        name: name,
        age: age,
        greet: function() {
            console.log(`Hello, my name is ${this.name}`);
        }
    };
}

const user = createUser('Alice', 30);
user.greet(); // 输出: Hello, my name is Alice

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

sayHello(); // 输出: Hello!
console.log(sayHello()); // 输出: Hello! undefined

function calculateDiscount(price, discountRate) {
    if (typeof price !== 'number' || typeof discountRate !== 'number') {
        return 'Invalid input';
    }
    return price * (1 - discountRate);
}

console.log(calculateDiscount(100, 0.1)); // 输出: 90
console.log(calculateDiscount('100', 0.1)); // 输出: Invalid input