Flowtype for json files

[kortina]

Is there a way to define a flowtype for a json file?

I manage a bunch of configuration files in json, and I would love to be able to define a schema for these files so that I can get warnings in my editor when updating them.

The way I imagine this working is perhaps either mapping *.sometype.json or file.json to a js file containing my type definitions in my ~/.flowconfig

Could you let me know if this is possible out of the box (or if you have ideas on how I might go about hacking this to work)?

[Benjamin-Dobell]

some/nested/path/yourJson.json

{
  "someThing": {
    "someKey": "Some value"
  }
}

flow-typed/yourJson.json.js

// some/nested/path/yourJson.json <-- This comment isn't at all necessary, just helpful
declare module './yourJson.json' {
    declare export type Thing = {
        someKey: string
    }

    declare var someThing: Thing
}

When you import types from yourJson.json, you can't do so using relative paths at various points through-out your project, as the module has only been declared for ./yourJson.json. So you must import types using the precise name of the module e.g.

import { someThing } from './yourJson.json'

import type { Thing } from './yourJson.json'

What I do to work around this is import the types into a JavaScript file (as above), then re-export them. Then I can use the types through-out the project importing them from the JavaScript file (using relative paths) as necessary.

Of course, don't forget to make sure your flow-config is loading the ./flow-typed dir i.e.

[libs]
./flow-typed

[goodmind]

This should be possible with file.json.flow files alongside file.json, but currently it resolves to any. I don't know why this is different from .js.flow files.