No suitable component definition found.

Haven't been able to get the JSON output for any component. However, that's working on the Playground app. For instance:

import React, { Component } from 'react';
import PropTypes from 'prop-types';
import './HSource.css';

export default class HSource extends Component {
  static propTypes = {
    url: PropTypes.string.isRequired,
  }

  render() {
    const { url } = this.props;
    return (
      <div
        className='source'
      >
        {url}
      </div>
    )
  }
} 

Ran with:

import HSource from '../../lib/HSource'
const reactDocs = require('react-docgen');
const componentInfo = reactDocs.parse(HSource)

Deps:

"dependencies": {
    "react": "^16.12.0",
    "react-dom": "^16.12.0",
    "react-scripts": "3.3.0"
  },
  "devDependencies": {
    "react-docgen": "^5.1.0"
  }

Still can't figure out if that's a bug, if that's my deps or if I'm missing something obvious...

Start by reproducing the example with react-docgen.parse(HSource) and compare it with the Playground behavior. Inspect the parser entry point involved in parsing this component and determine why no component definition is returned; done means the supplied component produces JSON output or the missing prerequisite is documented.