使用解构在ES6中定义可选参数

function greet({ name, age = 18, gender = 'unknown' }) {
  console.log(`Hello, my name is ${name}, I am ${age} years old, and I am ${gender}.`);
}

greet({ name: 'Alice' }); // 输出: Hello, my name is Alice, I am 18 years old, and I am unknown.
greet({ name: 'Bob', age: 25 }); // 输出: Hello, my name is Bob, I am 25 years old, and I am unknown.
greet({ name: 'Charlie', age: 30, gender: 'male' }); // 输出: Hello, my name is Charlie, I am 30 years old, and I am male.

function greet({ name, age = 18, gender = 'unknown' }) {
  console.log(`Hello, my name is ${name}, I am ${age} years old, and I am ${gender}.`);
}

greet({ name: 'Alice' }); // 正常输出

function greet({ user: { name, age = 18, gender = 'unknown' } }) {
  console.log(`Hello, my name is ${name}, I am ${age} years old, and I am ${gender}.`);
}

greet({ user: { name: 'Alice' } }); // 输出: Hello, my name is Alice, I am 18 years old, and I am unknown.