The most conveniant is to use directly the right emoji Unicode. Here a JSX example :
You can also use the node-emoji package to help you manipulate them.
If you want to know what unicode emoji to add, you can find this page useful : Full Emoji List
How to get a React element as an HTML string
For use cases, you may want to have the generated HTML string from your React component instead of a mounted component rendered on the page. The simplest way is to use the renderToString function provided by the react-dom package.
How to manage Internationalization with NextJS SSG
Staticaly generating a website with the NextJS framework in different languages is not so obvious.
Update NodeJS with npm
New NodeJS releases are done often, so you need to keep your installation up to date. To do so, you can use your Linux distribution package manager (apt, dnf, ...) or brew for OSX. Another way is to use npm..