如何解决异步问题？

function asyncOperation(callback) {
    setTimeout(() => {
        callback('异步操作完成');
    }, 1000);
}

asyncOperation((result) => {
    console.log(result);
});

function asyncOperation() {
    return new Promise((resolve, reject) => {
        setTimeout(() => {
            resolve('异步操作完成');
        }, 1000);
    });
}

asyncOperation().then(result => {
    console.log(result);
});

function asyncOperation() {
    return new Promise((resolve, reject) => {
        setTimeout(() => {
            resolve('异步操作完成');
        }, 1000);
    });
}

async function main() {
    const result = await asyncOperation();
    console.log(result);
}

main();

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

eventEmitter.on('asyncComplete', (result) => {
    console.log(result);
});

setTimeout(() => {
    eventEmitter.emit('asyncComplete', '异步操作完成');
}, 1000);

const pubsub = require('pubsub-js');

const token = pubsub.subscribe('asyncComplete', (msg, result) => {
    console.log(result);
});

setTimeout(() => {
    pubsub.publish('asyncComplete', '异步操作完成');
}, 1000);

// 记得取消订阅
// pubsub.unsubscribe(token);

async function main() {
    try {
        const result = await asyncOperation();
        console.log(result);
    } catch (error) {
        console.error('发生错误:', error);
    }
}

main();