Using promises with third-party libraries in Javascript

26 Oct 2023

In JavaScript, promises are a powerful tool for dealing with asynchronous operations. They allow us to write cleaner and more maintainable code, especially when working with third-party libraries.

Many third-party libraries, such as Axios, jQuery, or Firebase, provide their own APIs for asynchronous operations. However, these APIs may not always return promises natively. In such cases, we can wrap these APIs in promises to achieve a consistent and streamlined code structure.

Wrapping Third-Party Library Functions

To use promises with third-party libraries, we can encapsulate the library’s functionality within a promise. Here’s an example using Axios, a popular HTTP client library:

function makeApiCall(url) {
  return new Promise((resolve, reject) => {
    axios.get(url)
      .then(response => {
        resolve(response.data);
      })
      .catch(error => {
        reject(error);
      });
  });
}

In this example, we create a function called makeApiCall that takes a URL as a parameter. Inside the function, we create a new promise with the new Promise constructor. We then use axios to perform the actual API call, and handle the response and error using the promise’s resolve and reject methods.

By wrapping the Axios API call in a promise, we can use the async/await syntax or .then() and .catch() methods for handling the result of the API call.

Handling Multiple API Calls

In some cases, we may need to make multiple API calls and wait for all of them to complete before proceeding. JavaScript provides a handy method called Promise.all() that allows us to achieve this.

Here’s an example of making parallel API calls using Promise.all():

const urls = ['https://api.example.com/user/1', 'https://api.example.com/user/2', 'https://api.example.com/user/3'];

const apiCalls = urls.map(url => makeApiCall(url));

Promise.all(apiCalls)
  .then(responses => {
    // Handle responses here
  })
  .catch(error => {
    // Handle errors here
  });

In this example, we have an array of URLs that we want to make API calls to. We use the map() method to create an array of promises by calling the makeApiCall() function on each URL.

Then, we use Promise.all() to wait for all promises to resolve. Once all promises are resolved, the returned responses are passed to the .then() method. If any promise is rejected, the error will be caught by the .catch() method.

Conclusion

Using promises with third-party libraries in JavaScript allows us to streamline our code and handle asynchronous operations more effectively. By encapsulating the library’s functionality within promises, we can leverage the power of promises and achieve a more consistent code structure.

Remember to check the documentation of the library you are using to see if it provides a native promise API. If not, you can always wrap the library’s functions in promises to make them work seamlessly with your code.

Next time you work with a third-party library, consider using promises to handle its asynchronous operations. It will help your code become more readable, maintainable, and efficient.

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