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 the frontend is not reliable.

What you should do is, create an endpoint on a server that when called, responds with the correct response headers, thus triggering the browser download.

Frontend code can only do so much. The 'download' attribute for example, might just open the file in a new tab depending on the browser and the type of the file.

The response headers you need to look at are Content-Type and Content-Disposition. You should check this answer for a more detailed explanation on those headers.

tldr; fetch the file from the url, store it as a local Blob, inject a link element into the DOM, and click it to download the Blob

I had a PDF file that was stored in S3 behind a Cloudfront URL. I wanted the user to be able to click a button and immediately initiate a download without popping open a new tab with a PDF preview. Generally, if a file is hosted at a URL that has a different domain that the site the user is currently on, immediate downloads are blocked by many browsers for user security reasons. If you use this solution, do not initiate the file download unless a user clicks on a button to intentionally download.

In order to get by this, I needed to fetch the file from the URL getting around any CORS policies to save a local Blob that would then be the source of the downloaded file. In the code below, make sure you swap in your own fileURL, Content-Type, and FileName.

fetch('https://cors-anywhere.herokuapp.com/' + fileURL, {
    method: 'GET',
    headers: {
      'Content-Type': 'application/pdf',
    },
  })
  .then((response) => response.blob())
  .then((blob) => {
    // Create blob link to download
    const url = window.URL.createObjectURL(
      new Blob([blob]),
    );
    const link = document.createElement('a');
    link.href = url;
    link.setAttribute(
      'download',
      `FileName.pdf`,
    );

    // Append to html link element page
    document.body.appendChild(link);

    // Start download
    link.click();

    // Clean up and remove the link
    link.parentNode.removeChild(link);
  });

This solution references solutions to getting a blob from a URL and using a CORS proxy.

Update As of January 31st, 2021, the cors-anywhere demo hosted on Heroku servers will only allow limited use for testing purposes and cannot be used for production applications. You will have to host your own cors-anywhere server by following cors-anywhere or cors-server.

browsers are smart enough to detect the link and downloading it directly when clicking on an anchor tag without using the download attribute.

after getting your file link from the api, just use plain javascript by creating anchor tag and delete it after clicking on it dynamically immediately on the fly.

const link = document.createElement('a');
link.href = `your_link.pdf`;
document.body.appendChild(link);
link.click();
document.body.removeChild(link);