Feature: Support querystring on npm start

[coryhouse]

Some apps need to be started with querystring parameters. So it would be helpful to specify an optional querystring for npm start.

Suggested approach:

 "scripts": {
    "start": "react-scripts start --query=?foo=bar&baz=qux",
   ....

Thoughts?

[gaearon]

Hmm. Why not set up a redirect in src/index.js if this is absolutely required for the app?

[coryhouse]

Interesting. I hadn't considered that. The only downsides I see:

1. It's harder to find. Start would be the logical place I'd check first.
2. It would bubble up to all environments which is typically undesirable. Though this can be mitigated by checking the url for localhost so that redirecting only occurs in local dev.

The use case: App that is normally called from a separate app with required context provided via querystring.

I have the config above working on a fork of create-react-app, but I had to disable the Apple specific alternative to opn in react-dev-utils/openBrowser because it ignores querystrings.

[gaearon]

I think this is a bit of an unusual use case, and I don't think we'll be supporting this by default.
Maybe in the future as part of more general "default URL" customization.

[gaearon]

I think I'm going to close this unless there's more support for this being configurable. Since 0.9.0, you can override BROWSER environment variable to disable the default opening behavior (and potentially do something else in a custom script instead):

  "start": "BROWSER=none npm start && node scripts/myOpen.js"

[gaearon]

Seems like this use case will be fixed by #1590.