function fetchData(callback) {
    setTimeout(() => {
        callback('Data received');
    }, 1000);
}

fetchData((data) => {
    console.log(data); // 1秒后输出"Data received"
});

function fetchData() {
    return new Promise((resolve, reject) => {
        setTimeout(() => {
            resolve('Data received');
            // 或 reject(new Error('Failed'));
        }, 1000);
    });
}

fetchData()
    .then(data => console.log(data))
    .catch(error => console.error(error));

async function getData() {
    try {
        const data = await fetchData();
        console.log(data);
    } catch (error) {
        console.error(error);
    }
}

getData();

const EventEmitter = require('events');
const emitter = new EventEmitter();

emitter.on('data', (data) => {
    console.log('Received:', data);
});

setTimeout(() => {
    emitter.emit('data', 'Some data');
}, 1000);

function* asyncGenerator() {
    const result = yield new Promise(resolve => 
        setTimeout(() => resolve('Done'), 1000)
    );
    console.log(result);
}

const gen = asyncGenerator();
gen.next().value.then(val => gen.next(val));

// 模块中
const data = await fetchData();
console.log(data);

// 等待所有完成(可能有的失败)
Promise.allSettled([promise1, promise2])
    .then(results => {
        // 处理所有结果
    });

// 竞速模式
Promise.race([promise1, promise2])
    .then(firstResult => {
        // 处理第一个完成的结果
    });

const controller = new AbortController();
const signal = controller.signal;

fetch(url, { signal })
    .then(response => response.json())
    .catch(err => {
        if (err.name === 'AbortError') {
            console.log('Fetch aborted');
        }
    });

// 取消请求
controller.abort();