What are some examples of promise chaining in JavaScript?

What are some examples of promise chaining in JavaScript?

Promise chaining is a way to execute asynchronous operations in sequence. For example, you can fetch data from an API, process it, and then display it. Here's a simple example:

fetch('https://api.example.com/data')
  .then(response => response.json())
  .then(data => processData(data))
  .then(result => displayResult(result))
  .catch(error => console.error('Error:', error));

Can you explain each step in that example?

Sure! In the example:

1. fetch initiates a request to the API.
2. The first .then converts the response to JSON.
3. The second .then processes the data returned from the API.
4. The third .then displays the processed result.
5. If any step fails, the .catch handles the error.

What if I want to handle multiple promises at once?

You can use Promise.all() to handle multiple promises concurrently. For example:

Promise.all([promise1, promise2])
  .then(results => {
    // results is an array of resolved values
  })
  .catch(error => console.error('Error:', error));

Are there any drawbacks to promise chaining?

Yes, one drawback is that if any promise in the chain fails, the entire chain is rejected. This can make error handling more complex if you need to handle errors from multiple promises differently.