Working with TypeScript Promise APIs

Working with TypeScript Promise APIs

Promises have become a popular way for working with asynchronous programming in TypeScript. Promises are objects that represent the eventual completion or failure of a task, such as an API request. They enable you to chain multiple requests and coordinate the flow of control execution between them. In this post, we’ll explore TypeScript Promise APIs and how to use them in your TypeScript applications.

What is a Promise?

A Promise represents the result of an asynchronous operation such as an API call. When you make the initial call, the promise object is returned to you immediately. The promise object will either resolve (success) or reject (fail) when the operation is complete. Depending on the resolution, different callbacks are triggered and executed, allowing you to chain multiple operations together.

Using TypeScript Promise APIs

Typescript provides several options for creating and working with Promise APIs. The easiest way to get started is by using the built-in global promise constructor. This constructor accepts two parameters: a callback that will be invoked when the promise is successfully resolved, and a callback that will be invoked if the promise fails. For example:

const apiPromise = new Promise((resolve, reject) => {
    // Code to run the API call
    // ...

    if (apiCallSucceeded) {
        resolve('API call successful!');
    } else {
        reject('API call failed :(');
    }
});

Once the promise is created, it can be used with the then() method. The then() method accepts two callbacks, one for handling the success case and one for handling the failure case. For example:

apiPromise.then(
    (result: string) => {
        // Handle the success case here.
        console.log(result);
    },
    (error: any) => {
        // Handle the failure case here.
        console.error(error);
    }
);

Conclusion

Promises are a great way to handle asynchronous operations in TypeScript. By using the built-in global promise constructor and the then() method, you can easily work with TypeScript Promise APIs and chain multiple operations together. Try incorporating promises into your TypeScript code today!