How can I make React open a new tab only once?

edit

You can use the useEffect hook to check whether the component has already mounted and then use window.open() to open a new tab only if the component is mounted for the first time. Here's an example:

import React, { useEffect } from 'react';

function MyComponent() {
  useEffect(() => {
    const isOpened = localStorage.getItem('isOpened');
    if (!isOpened) {
      window.open('https://www.example.com', '_blank');
      localStorage.setItem('isOpened', true);
    }
  }, []);

  return <div>Hello world!</div>;
}

export default MyComponent;

In this example, we're using localStorage to store a flag (isOpened) that indicates whether the new tab has been opened before. By default, isOpened is null, so on the first mount of the component, the new tab will be opened and isOpened will be set to true. On subsequent mounts, isOpened will have a value of true, so the new tab won't be opened again.