[Feature] Pass through environment variables

[mikeduminy]

Do you want to request a feature or report a bug? Feature

What is the current behavior? Environment variables set outside of metro server are not available in the initial bundle of the

What is the expected behavior? Webpack allows explicit environment variable pass through to bundle via a plugin. https://webpack.js.org/plugins/environment-plugin/

I'd like this sort of thing to be supported in metro too.

[wnatrifork]

There is already a babel plugin for such a feature: https://www.npmjs.com/package/babel-plugin-transform-inline-environment-variables

However, there's an error in the documentation. The .babelrc configuration should look like this:

{
  "plugins": ["babel-plugin-transform-inline-environment-variables"]
}