How are the 'async' and 'await' keywords used in JavaScript?

The async and await keywords were introduced in ES2017 and provide a way to write asynchronous code that looks and behaves like synchronous code. The async keyword is used to define an asynchronous function, which will always return a promise. The await keyword can be used inside an async function to pause the execution of the function until a promise is resolved. Here's an example of how async and await can be used to fetch data from a remote server:

async function fetchData() {
  try {
    const response = await fetch('https://example.com/data');
    const data = await response.json();
    console.log(data);
  } catch (error) {
    console.error(error);
  }
}

In this example, the fetchData function is declared as an async function, which means that it will always return a promise. Inside the function, the await keyword is used twice: first to wait for the response from the server, and then to wait for the data to be parsed as JSON. The try...catch block is used to handle any errors that may occur during the asynchronous operation.