How do I handle promises in Express.js?

How do I handle promises in Express.js?

In Express.js, you can handle promises using async/await or by chaining .then() and .catch() methods. Which one would you like to know more about?

Can you explain how to use async/await?

Sure! You can define your route handler as an async function. For example:

app.get('/data', async (req, res) => {
    try {
        const data = await getData(); // Assume getData() returns a promise
        res.json(data);
    } catch (error) {
        res.status(500).send('Error retrieving data');
    }
});

This way, you can handle errors using try/catch.

What if I want to handle multiple promises?

You can use Promise.all to handle multiple promises concurrently. Here's an example:

app.get('/multiple-data', async (req, res) => {
    try {
        const [data1, data2] = await Promise.all([getData1(), getData2()]);
        res.json({ data1, data2 });
    } catch (error) {
        res.status(500).send('Error retrieving data');
    }
});