Web Development Frameworks 4

Question 1

What is the role of `forwardRef` in React?

Accepted Answer

Allows a parent component to access a child component's DOM node or instance via a ref

Answer

forwardRef lets a component pass a ref it receives down to a DOM element or another component, enabling parent components to interact with child DOM nodes.

Question 2

In Vue 3, what is the key difference between `ref()` and `reactive()`?

Accepted Answer

ref() wraps any value and accesses it via .value; reactive() makes a plain object deeply reactive

Answer

ref() wraps any value type and requires .value access in JavaScript, while reactive() takes a plain object and makes all its properties reactive without .value.

Question 3

What is Angular's change detection strategy `OnPush` used for?

Accepted Answer

Limits change detection to run only when input references change or events fire within the component

Answer

OnPush tells Angular to skip change detection for a component subtree unless an input reference changes, an event originates within it, or it's manually marked for check.

Question 4

Which Express.js method correctly handles errors passed via `next(err)`?

Accepted Answer

An error-handling middleware with signature (err, req, res, next)

Answer

Express identifies error-handling middleware by its four-parameter signature (err, req, res, next); the extra `err` parameter distinguishes it from regular middleware.

Question 5

What is hydration in the context of server-side rendered React applications?

Accepted Answer

The process of attaching React event listeners to server-rendered HTML already in the DOM

Answer

Hydration is when React takes over static HTML rendered by the server, attaches event listeners, and makes the page fully interactive without re-rendering the DOM.

Web Development Practice Test

Web Development Practice Test

Web Development Frameworks 4