从js代码派生动态生成的值

function calculateSum(a, b) {
    return a + b;
}
let sum = calculateSum(3, 5); // sum 现在是 8

let obj = {};
obj.dynamicProperty = 'Hello, World!';
console.log(obj.dynamicProperty); // 输出 'Hello, World!'

let arr = [1, 2, 3];
arr.push(4); // arr 现在是 [1, 2, 3, 4]

let numbers = [1, 2, 3, 4, 5];
let evenNumbers = [];
for (let num of numbers) {
    if (num % 2 === 0) {
        evenNumbers.push(num);
    }
}
// evenNumbers 现在是 [2, 4]

function createCounter() {
    let count = 0;
    return function() {
        count++;
        return count;
    };
}
let counter = createCounter();
console.log(counter()); // 输出 1
console.log(counter()); // 输出 2

function fetchData() {
    return new Promise((resolve, reject) => {
        setTimeout(() => {
            resolve('Data fetched');
        }, 1000);
    });
}

async function getData() {
    let data = await fetchData();
    console.log(data); // 输出 'Data fetched'
}

getData();