how to download file in react js
This is not related to React. However, you can use the download attribute on the anchor <a> element to tell the browser to download the file.
<a href='/somefile.txt' download>Click to download</a>This is not supported on all browsers: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/a
If you are using React Router, use this:
<Link to="/files/myfile.pdf" target="_blank" download>Download</Link>Where /files/myfile.pdf is inside your public folder.
Triggering browser download from front-end is not reliable.
What you should do is, create an endpoint that when called, will provide the correct response headers, thus triggering the browser download.
Front-end code can only do so much. The 'download' attribute for example, might just open the file in a new tab depending on the browser.
The response headers you need to look at are probably Content-Type and Content-Disposition. You should check this answer for more detailed explanation.