Async Stuff

Promises are a useful tool for working with asynchronous code in JavaScript because they provide a way to handle the results of asynchronous operations consistently and predictably. However, promises can be somewhat complex to work with, because they require you to use callback functions and manage the state of the promise.

The async and await keywords in TypeScript provide a way to simplify working with promises by allowing you to write asynchronous code that looks and behaves like synchronous code. When you use async and await, you can use the await keyword to wait for the result of a promise, and the code that follows the await keyword will be executed only when the promise is resolved. This makes it easier to write asynchronous code that is easy to read and understand.

However, it is important to note that async and await are just syntax sugar on top of promises. They are not a completely different way of writing asynchronous code, but rather a way to make promises easier to work with. Behind the scenes, async and await still use promises to manage the flow of asynchronous operations.

You can use the built-in Promise type to specify the type of a promise. The Promise type is a generic type that takes two type arguments: the type of the resolved value of the promise, and the type of the rejected value of the promise.

For example, if you have a promise that resolves to a string and rejects with an Error object, you could specify the type of the promise like this:

let promise: Promise<string, Error>;

In this code, the Promise<string, Error> type specifies that the promise variable is a promise that resolves to a string and rejects with an Error object.

You can also use the Promise type to specify the type of a function that returns a promise. For example, if you have a function that returns a promise that resolves to a string and rejects with an Error object, you could specify the type of the function like this:

function someAsyncFunction(): Promise<string, Error> {
  // asynchronous code goes here
}

In this code, the Promise<string, Error> type specifies that the someAsyncFunction() function returns a promise that resolves to a string and rejects it with an Error object.

The Promise type in TypeScript is a useful tool for specifying the type of a promise, and it allows you to specify the type of the resolved and rejected values of the promise. This can help to ensure that your code is correct and free of type errors.