Storysource unable to parse Flow type annotations

[Nemvts]

Describe the bug
Storysource is unable to parse Flow type annotations. When the type annotations are removed or by wrapping it around a flow comment the error will go away.

Code snippets
Error message from Console

./src/form/form.stories.js
Module build failed: SyntaxError: Unexpected token (43:5)

Flow example resulting in error

type ContactRawFormProps = {
  handleSubmit: Function,
};
const ContactRawForm = (props: ContactRawFormProps) 

System:

• OS: Windows10
• Browser: Chrome
• Framework: React
• Addons:

    "@storybook/addon-backgrounds": "3.4.8",
    "@storybook/addon-knobs": "3.4.8",
    "@storybook/addon-notes": "3.4.8",
    "@storybook/addon-storysource": "3.4.8",

• Version:
  "babel-core": "6.26.3",

Additional context
webpack.config.js

      {
        test: /\.stories\.js?$/,
        exclude: [
          path.resolve(__dirname, '../src/old-components'),
          path.resolve(__dirname, '../src/deprecated'),
        ],
        use: [
          {
            loader: require.resolve('@storybook/addon-storysource/loader'),
            options: {
              prettierConfig: {
                parser: 'babylon',
              },
              uglyCommentsRegex: [/^::/],
            },
          },
        ],
        enforce: 'pre',
      },

[igor-dv]

Storysource is dependant on parsers from Prettier and works now with prettier/parser-babylon and prettier/parser-typescript. For Flow they have a prettier/parser-flow.

It's very easy to add a support for this, would you like to create a PR ?

[Nemvts]

@igor-dv Babel v7 seems to now support Flow syntax so maybe this is not actually needed, but PR #4971 has been created to add support for Flow as an option.

For Reference

[igor-dv]

babel supported Flow before as well (IMO), but the current implementation is not relying on babel directly