Q371. What is a debugger statement?
The debugger statement invokes any available debugging functionality, such as setting a breakpoint. If no debugging functionality is available, this statement has no effe...
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Q372. How do you render Array, Strings and Numbers in React 16 Version?
**Note:** This question references React 16. These features remain valid in current React versions (18/19). **Arrays**: Starting with React 16, you can return multiple si...
Q373. How do you handle not-found pages in App Router?
You can create custom not-found pages using the `not-found.js` file. This file defines UI to render when the `notFound()` function is thrown within a route segment. ```js...
Q374. What is the purpose of breakpoints in debugging?
You can set breakpoints in the javascript code once the debugger statement is executed and the debugger window pops up. At each breakpoint, javascript will stop executing...
Q375. What are hooks?
Hooks is a special JavaScript function that allows you use state and other React features without writing a class. This pattern has been introduced as a new feature in Re...
Q376. What is the template.js file in App Router?
The `template.js` file is similar to `layout.js` but creates a new instance for each of its children on navigation. This means state is not preserved and effects are re-s...
Q377. Can I use reserved words as identifiers?
No, you cannot use the reserved words as variables, labels, object or function names. Let's see one simple example, ```javascript var else = "hello"; // Uncaught SyntaxEr...
Q378. How do you implement nested layouts in App Router?
Nested layouts are implemented by creating `layout.js` files in different route segments. Layouts are nested automatically based on the folder structure. ``` app/ ├── lay...
Q379. How do you detect a mobile browser?
You can use regex which returns a true or false value depending on whether or not the user is browsing with a mobile. ```javascript window.mobilecheck = function () { var...
Q380. What are route handlers vs API routes in App Router?
In the App Router, API routes are now called "Route Handlers" and use the `route.js` file convention instead of the pages-based approach. **Pages Router (API Routes)**: `...