The Modern JavaScript Bootcamp (2019) - The Fetch API

The video tutorial introduces the Fetch API as a modern alternative to XMLHttpRequest for making HTTP requests in JavaScript. It explains how Fetch API integrates promises, allowing for cleaner and more efficient code through promise chaining. The tutorial covers handling responses and errors, converting existing XMLHttpRequest code to use Fetch, and advanced promise chaining techniques. The video concludes with a challenge for viewers to apply these concepts independently.

What is the primary advantage of using the Fetch API over XML HTTP requests?

• It is faster.

• It is easier to read.

• It is more secure.

• It has built-in promise support.

When using the Fetch API, what does the 'then' method allow you to do?

• Retry the request.

• Cancel the request.

• Handle the response data.

• Log the request details.

What is the purpose of the 'catch' method in a promise chain?

• To modify the request headers.

• To log the request details.

• To handle errors that occur during the request.

• To handle successful responses.

How can you check if a Fetch API request was successful?

• By checking the response time.

• By checking the response status code.

• By checking the response headers.

• By checking the response size.

What does the 'JSON' method of a Fetch API response return?

• A string.

• A promise that resolves to a JavaScript object.

• A number.

• An array.

In the context of Fetch API, what does returning a promise from a 'then' method allow?

• It allows chaining another 'then' method.

• It cancels the request.

• It modifies the request headers.

• It logs the request details.

What is the benefit of abstracting promise chains into functions?

• It allows for more complex error handling.

• It increases the security of the code.

• It reduces code duplication and improves readability.

• It makes the code run faster.

What happens if you return a non-promise value from a 'then' method?

• The promise chain stops.

• An error is thrown.

• The request is retried.

• The next 'then' method receives the value.

How can you ensure that a function using Fetch API returns a promise?

• By using async/await.

• By using a setTimeout function.

• By using a callback function.

• By returning the result of a Fetch call.

What is a common source of confusion for beginners when using promise chains?

• Understanding how to handle errors.

• Understanding how to parse JSON data.

• Understanding how to make HTTP requests.

• Understanding how to chain multiple 'then' methods.