The Modern JavaScript Bootcamp (2019) - Exploring Promises

The video tutorial introduces promises in JavaScript, highlighting their advantages over callbacks for structuring asynchronous code. It explains how to set up promises, compares them with callbacks, and demonstrates error handling in both approaches. The tutorial emphasizes the clearer semantics and single execution nature of promises, making them easier to reason about. It concludes with a preview of integrating promises into existing applications.

What is one of the main benefits of using promises over callbacks in JavaScript?

• They are supported in all browsers.

• They require less code to implement.

• They execute faster than callbacks.

• They are easier to read and manage.

What is the purpose of using setTimeout in the context of promises?

• To create a new promise.

• To make HTTP requests.

• To simulate a delay in code execution.

• To handle errors in promises.

Which method is used to handle the result of a promise once it resolves?

• catch

• resolve

• then

• finally

What is the role of the 'then' method in promises?

• To create a new promise.

• To reject a promise.

• To handle errors in promises.

• To define actions after a promise resolves.

How can you handle errors in a promise?

• By using the reject method.

• By using the finally method.

• By using the resolve method.

• By using the catch method.

In the context of promises, what does the 'reject' function do?

• It indicates that the promise has failed.

• It handles the promise's success case.

• It creates a new promise.

• It resolves the promise with a value.

What is a key advantage of promises in terms of error handling?

• Errors are automatically logged to the console.

• Errors are resolved automatically.

• Errors can be handled separately from success cases.

• Errors are less likely to occur.

What happens if you call resolve or reject multiple times in a promise?

• The promise will reset.

• It will throw an error.

• Only the first call will be considered.

• The promise will execute multiple times.

Why are promises considered to have clearer semantics than callbacks?

• They use specific functions for success and failure.

• They are more widely supported.

• They are faster to execute.

• They require less code.

How can you perform multiple actions with the same promise result?

• By using the catch method.

• By calling resolve multiple times.

• By creating multiple promises.

• By using multiple then methods.