How to use env in index.html within a react vite application

Question

I'm trying to access an env variable from my index.html file.

The code below seems to work in CRA but doesnt work with my vite, react project setup

const APP_ID = '%REACT_APP_ID%'

    <script>
      //Set your APP_ID
      const APP_ID = '%REACT_APP_ID%'

     ....

    </script>

my vite config file

import { defineConfig, splitVendorChunkPlugin } from 'vite'
import react from '@vitejs/plugin-react'
import EnvironmentPlugin from 'vite-plugin-environment'

// https://vitejs.dev/config/
export default defineConfig({
  plugins: [
    splitVendorChunkPlugin(),
    react(),
    EnvironmentPlugin('all', { prefix: 'REACT_APP_' }),
  ],
})

Answer 1

Replacing environment variables in HTML files is supported since Vite 4.2.0.

Define environment variables with the VITE_ prefix, and wrap it between % in the HTML file.

For example:

<div>%VITE_SOME_KEY%</div>

Answer 2

You should to use only "%YOUR_VAR%" like this:

<script type="text/javascript">
    const flag = "%VITE_TRACKING_ID%" 
          if (flag) {
            ...
</script>

have in mind you would need to update your Vite 4.2.0 as commented @Unmitigated

this is the thread to fix https://github.com/vitejs/vite/issues/3105#issuecomment-1441947641