javascript。使用包含变量项的map在数组中迭代

const people = [
  { name: 'Alice', age: 25 },
  { name: 'Bob', age: 30 },
  { name: 'Charlie', age: 35 }
];

const updatedPeople = people.map(person => ({
  name: person.name,
  age: person.age + 1
}));

console.log(updatedPeople);
// 输出: [{ name: 'Alice', age: 26 }, { name: 'Bob', age: 31 }, { name: 'Charlie', age: 36 }]

const numbers = [1, 2, 3, 4, 5];

// 错误的示例
const doubledNumbers = numbers.map(num => {
  num * 2; // 没有返回值
});

console.log(doubledNumbers); // 输出: []

// 正确的示例
const doubledNumbers = numbers.map(num => num * 2);

console.log(doubledNumbers); // 输出: [2, 4, 6, 8, 10]

const emptyArray = [];

const result = emptyArray.map(num => num * 2);

console.log(result); // 输出: []

const numbers = [1, 2, 3, 4, 5];

const filteredNumbers = numbers.map(num => {
  if (num > 3) {
    return num * 2;
  }
  // 没有返回值的情况
});

console.log(filteredNumbers); // 输出: [undefined, undefined, undefined, 8, 10]

// 正确的示例
const filteredNumbers = numbers.map(num => {
  if (num > 3) {
    return num * 2;
  }
  return num; // 确保有返回值
});

console.log(filteredNumbers); // 输出: [1, 2, 3, 8, 10]