[SOLVED] Flow libdefs for libraries with deeper paths

Flow libdefs for libraries with deeper paths

I'm testing out Flow for typing our JavaScript, and I want to create a libdef for an internal library. It's imported like this:

import withValidation from 'internally-shared-libs/decorators/withValidation';

The documentation doesn't really address how to create library definitions for deep paths like this - only top level ones.

Where do I put the libdef file? What do I call it? And how would it look (ignoring the actual implementation of the libdef, of course)?

Thanks in advance for any help on this!

Solution

You can have multiple declare module in a single libdef. You can use a deep path as the module name. It doesn't matter where this libdef file is as long as it is included in the [libs] section in your .flowconfig.

Here's an example where internally-shared-libs has exports as well as deeper paths having exports:

Libdef:

// @flow

declare module 'internally-shared-libs' {
  declare export function hello(): string;
  declare export function bye(): string;
}

declare module 'internally-shared-libs/decorators/withValidation' {
  // You will obviously want to improve these types
  declare type Input = any;
  declare type Output = any;
  declare export default function withValidation(input: Input): Output;
}

Usage:

// @flow

import { hello, bye } from 'internally-shared-libs';
import withValidation from 'internally-shared-libs/decorators/withValidation';