Use leaflet and react-leaflet as external packages

[pikhovkin]

I propose to make the leaflet and the react-leaflet external. This would allow development of plugins for the dash-leaflet. This would allow you to take your existing plugins outside and develop them as separate python packages.
Developing, maintaining, and updating new plugins will be faster with the help of the community.
I want to make a plugin for the dash-leaflet based on the leaflet-geoman.

[emilhe]

That sounds interesting. The diff is rather huge at the point, could you comment on what you changed?

[pikhovkin]

The main files and main changes are

• webpack.config.js

    const externals = ('externals' in overrides) ? overrides.externals : ({
        react: 'React',
        'react-dom': 'ReactDOM',
        'plotly.js': 'Plotly',
        'prop-types': 'PropTypes',
        'leaflet': 'L',  // <<
        'react-leaflet': 'ReactLeaflet',  // <<
    });

• dash_leaflet dir - I added leaflet@1.7.1.css, leaflet@1.7.1.js, react-leaflet@2.8.0.js
• dash_leaflet/__init__.py - I plugged in the scripts and styles above

The other files changed on their own during compilation. You might as well not merge them.

[pikhovkin]

I made dash-leaflet-measure external plugin based on your internal plugin for an example. Here is an example of how to use

[pikhovkin]

I also prepare the ground for the dependencies between the Dash components to work. You could support my pull request.

[emilhe]

I am not sure that I can merge only part of the PR (do you have a link on docs on how to do so?). Otherwise, would it be possible for you to just include the files with relevant changes?¨

In your example, you explicitly specify,

app.scripts.config.serve_locally = True
app.css.config.serve_locally = True

Is that necessary for the custom component to work?

[pikhovkin]

Otherwise, would it be possible for you to just include the files with relevant changes?

I'l try to change the pull request

Is that necessary for the custom component to work?

Yes, this component (its scripts) is not registered with unpkg, so its scripts are only available locally.