Which keyword is used to define an asynchronous function in JavaScript?
async
sync
promise
await
How can you handle errors inside an async function?
Errors cannot be handled inside async functions.
By calling the .catch() method on the async function itself.
.catch()
By using the throw keyword.
throw
Using a try...catch block.
try...catch
Which principle of object-oriented programming focuses on hiding internal implementation details and exposing only necessary information?
Inheritance
Abstraction
Encapsulation
Polymorphism
Which HTTP status code range generally indicates a successful request made with the Fetch API?
100-199
300-399
200-299
400-499
Which of the following is NOT a valid HTTP method used with the Fetch API?
POST
CONNECT
GET
DELETE
What is the impact of long-running JavaScript tasks on the browser's responsiveness?
They improve rendering performance by allowing the browser to optimize resource allocation.
They have no significant impact on browser responsiveness, as JavaScript execution is asynchronous.
They enhance user experience by providing smoother animations and transitions.
They can block the main thread, leading to a frozen UI and unresponsive interactions.
What is the primary role of the this keyword in JavaScript?
this
It creates a new object instance.
It refers to the current date and time.
It accesses the global scope.
It points to the object that the function is a property of, determined at function call time.
How does the 'bind()' method in JavaScript differ from 'call()' and 'apply()'?
bind() can only be used with object methods, while call() and apply() can be used with any function.
bind() doesn't modify the original function, while call() and apply() do.
bind() creates a new function with a bound 'this' context, while call() and apply() invoke the function immediately.
bind() immediately invokes the function, while call() and apply() don't.
How can you ensure that the 'this' keyword inside a callback function refers to the intended object, especially in asynchronous operations?
By invoking the callback function with 'call()' or 'apply()'.
By using arrow functions, which lexically inherit the 'this' value.
By using the 'let' keyword to declare variables inside the callback.
By wrapping the callback function in another function.
What is the primary purpose of constructor functions in JavaScript?
To handle asynchronous operations.
To define static methods for a class.
To define private variables within a function scope.
To create multiple instances of an object with shared properties and methods.