When working with APIs that require multiple sequential requests, it can become challenging to handle the response and ensure all the requests are executed correctly. One way to handle this situation is by using promise chaining.

In JavaScript, promises are a powerful tool for handling asynchronous operations. By utilizing promise chaining, we can make multiple API requests and ensure they are resolved in a sequential manner.

Let’s consider an example where we need to fetch data from two different endpoints and then perform some processing on the received data.

fetch('https://api.example.com/endpoint1')
  .then(response => response.json())
  .then(data1 => {
    // Process data1

    return fetch('https://api.example.com/endpoint2');
  })
  .then(response => response.json())
  .then(data2 => {
    // Process data2

    // Perform further actions with data1 and data2
  })
  .catch(error => {
    // Handle any errors that occurred during the API requests
  });

In the code snippet above, we first make a request to https://api.example.com/endpoint1 using the fetch function. Once the response is fetched, the first .then block is executed, where we process the data1 received from endpoint1.

Next, we return another fetch request to https://api.example.com/endpoint2 in the first .then block. This ensures that the second API request is made only after the first one is successfully completed.

In the second .then block, we receive the response from endpoint2 and process data2. Finally, we can perform any further actions requiring both data1 and data2.

If any error occurs during any of the API requests, the .catch block will be triggered, allowing us to handle the error accordingly.

Promise chaining simplifies the handling of multiple sequential API requests by ensuring that each request is executed only after the previous one is resolved. It also provides a clean and readable syntax to handle asynchronous operations.

Conclusion

Promise chaining is a powerful technique to handle multiple API requests in a sequential manner. It allows us to fetch data from different endpoints and process them using a clean and readable syntax. By utilizing promise chaining, we can ensure that each request is executed in the intended order, making our code more efficient and manageable.

#javascript #API #promises