Modern JavaScript from the Beginning - Second Edition - Under the Hood: How Async JS Works

The video tutorial provides an in-depth look at asynchronous JavaScript, explaining the differences between blocking and non-blocking code. It covers the JavaScript engine, the role of the event loop, and how task queues operate. The tutorial also introduces promises and the Fetch API, highlighting their use in handling asynchronous operations. The video aims to demystify these concepts, preparing viewers for more advanced topics in asynchronous JavaScript.

What is the default nature of JavaScript in terms of execution?

• Asynchronous and multi-threaded

• Asynchronous and single-threaded

• Synchronous and single-threaded

• Synchronous and multi-threaded

Which method is used for non-blocking file reading in Node.js?

• readFileSync

• readFile

• readFileAsync

• readFileNonBlocking

What does the call stack in JavaScript represent?

• A stack of functions to be executed

• A queue of completed operations

• A list of asynchronous tasks

• A heap of memory allocations

Which of the following is NOT part of the core JavaScript language?

• if statement

• setTimeout

• console.log

• for loop

What is the role of the event loop in JavaScript?

• To manage memory allocation

• To execute synchronous code

• To monitor the call stack and task queue

• To handle errors in code

How do promises differ from callbacks in JavaScript?

• Promises are part of the core JavaScript language

• Promises are faster than callbacks

• Promises use a microtask queue, callbacks use a task queue

• Promises are synchronous, callbacks are asynchronous

What is the priority difference between the task queue and the microtask queue?

• Task queue has higher priority

• Both have the same priority

• Priority depends on the environment

• Microtask queue has higher priority