Add a console warning when browser bundle is loaded in node.

[hsubox76]

Partially addresses issue #1415.

Open to suggestions on what the message should recommend to the user.

Tried a rollup node test project and browser webpack test project. Warning is seen in node, not seen in browser.

[Feiyang1]

It's not clear to me what ES module resolution means. It's probably better to just state please use the "main" field in package.json for node bundle.
We can also add the link to webpack doc - https://webpack.js.org/configuration/resolve/#resolvemainfields
and rollup doc - https://github.com/rollup/rollup-plugin-node-resolve

[hsubox76]

Modified the text.

[arpowers]

The solution you guys are proposing is not going to work. Also you give no ways of debugging this issue since Webpack is compiling normally with the 'node' target set.

[arpowers]

it says here:
https://webpack.js.org/configuration/resolve/#resolvemainfields

A node targeted Webpack build will load 'module' first, YET, you've added this warning to the index.esm.js entry ( which is the firebase entry for 'module' )

Also changing Webpack global config is NEVER going to work - as you'll cause way worse bugs from other packages with this approach.

Also things were working fine for me before, and you guys have not provided a way to disable this huge warning message.

@Feiyang1 @hsubox76

[Feiyang1]

Thank you for the feedback. And sorry you had a bad experience.

To clarify how fields are used in firebase currently:
main: cjs build for Node
module: esm build for browser
browser: cjs build for browser
react-native: cjs build for react-native

Each firebase SDK (except storage) does something different for Node, so the browser version should really not be used for Node environment. and it could cause issues down the road if you are already using it, so I think the warning message is warranted.

We have both cjs and esm build for browser because we want to support as many workflow as possible, for example, browserify only works with cjs natively.

I'd like to have a browser-module field, so I can use module field to point to node version, but I don't think there is something like this at the moment, so we chose to use the module field for the browser build.

I'm open to suggestions, but given the constraint of a single module field, I don't know what more we can do than giving a warning message when a bundle is used in the unintended environment.

I'm not convinced that changing the global resolve.mainFields to read main field first is going to cause issue for other packages as all node packages should have a cjs build pointed by the main field.

If you are really worried about it, you could do something like:

  resolve: {
    alias: {
      firebase$: path.resolve(__dirname, 'node_modules/firebase/dist/index.node.cjs.js')
    }
  }

Anyway, thanks for voicing your concern. If you'd like to continue the discussion, please open an issue, so we can track it.