Next js Interview Questions and Answers
If you are a Next JS aspirant and preparing for your next big day, continue further to get the knowledge of best Next JS interview questions with answers selected by industry experts. Greatly inspired by PHP, Next JS is a JavaScript framework that can be used to create static as well as server-side rendering web applications and websites using React library. It allows users to export application components to perform individual tests for each of them. Next JS also allows developers to download thousands of modules from npm.
- Easy installation, project build, modification, and required package found.
- Optimal application performance due to the availability of automatic code splitting.
- Next JS allows optimized code bundles to be loaded lazily behind the scenes with the help of prefetching.
- It allows application code to use SSR or Server Side Rendering, thus offering SEO friendly flexibility, initial render to application view, and elimination of code download.
- Effective Hot-Module Replacement and powerful error reporting.
Most Frequently Asked Next js Interview Questions
Next, JS is an open-source, JavaScript framework that lets developers build static and server-side rendering web applications. Created by Zeit, Next JS doesn’t require any Webpack configuration and only needs npm run dev start building your next feature filled web application.
Developers will need NPM to start installing Next JS with all its dependencies. Here are the steps to follow:
- Create a directory to keep the Next JS project and go into it:
mkdir my-portfolio-site
cd my-portfolio-site - Now initialize this with a package.json file.
- Use the y flag by npm init –y
- Use the below-mentioned syntax to install Next JS
npm install react react-dom next - Update package.json with run script languages to start the initialization of Next JS application.
- Please find the package.json file on root folder and add the below mentioned script
"dev": "next",
"build": "next build",
"start": "next start"
Now, we are finished with the process.
Here is a list of most developer-exciting Next JS features:
- Default and easy server rendering
- Static exporting
- Hot code reloading
- Automatic code splitting
- Complete Webpack and Babel control
- Filesystem based routing
- Faster and optimized development compilation
To disable etag generation in Next JS, we have to use the app.disable('etag') syntax. But, this may not work for all static contents. The below mentioned syntax will disable etag for all static contents.
app.use(express.static(path.join(__dirname, 'public'), {
etag: false
}));
- To create a custom error page in Next JS, we have to define a “_error.js” in the page folder with this given syntax.
- We have to import our own “_ error” component instead of “next/error” further to use our custom error page.
import React from 'react';
class Error extends React.Component {
static getInitialProps({ res, err }) {
const statusCode = res ? res.statusCode : err ? err.statusCode : null;
return { statusCode };
}
render() {
return (
<p>
{this.props.statusCode
? `An error ${this.props.statusCode} occurred on server`
: 'An error occurred on client'}
</p>
);
}
}
export default Error;
Developers have to follow these steps to setup CDN in Next JS.
- To start, we have to first set up the “assetPrefix” setting and configure our CDN origin to support resolve to the domain that our Next JS is hosted on.
const isProd = process.env.NODE_ENV === 'production';
module.exports = {
// You may only need to add assetPrefix in the production.
assetPrefix: isProd ? 'https://cdn.mydomain.com' : ''
};
- For a CDN present on a separate domain that you may like assets to be requested with use of CORS aware request, we have to set a configuration option as following.
// next.config.js
module.exports = {
crossOrigin: 'anonymous'
};
To configure a static ID between our builds, we have to provide “generateBuildId” function with this given configuration.
// next.config.js
module.exports = {
generateBuildId: async () => {
// For example get the latest git commit hash here
return 'my-build-id';
}
};
We have to use the further mentioned syntax configuration to write inline CSS in Next JS.
function HiThere() {
return <p style={{ color: 'red' }}>hi there</p>;
}
export default HiThere;
This is a Next JS standard used to build high-performance websites rendering overhead. AMP implemented websites are indexed faster in modern and popular search engines with enhanced promoting behavior. AMP web pages are loaded directly to Google's mobile search results with a lightning icon, better performance, fewer restrictions, and better scalability.
Here is a list of advance Next JS interview questions with most appropriate answers suitable best for both freshers as well as experienced developers of this niche to practice.
Latest Version
Latest version of next js is v8.1.1