Support custom result marker popups via callback

[nickdaugherty]

It should be easy to customize the marker popup content by passing a function to the Geocoder options that takes a Pelias result as an argument and returns an html string or DOM element to be used as the marker popup.

L.control.geocoder( <api_key>, {
    ...
    markersPopup: function( result ) {
        // Create popup content here
        return result.properties.label;
    }
    ...
});

[louh]

Thanks for the suggestion, @nickdaugherty. I'm contemplating how we might be able to pass through all of the Popup options available on Leaflet as well. This is far from a fully thought out proposal, but I imagine it may be something that extends the options object, like so:

L.control.geocoder( <api_key>, {
    ...
    popup: {
        // Leaflet popup options
        maxWidth: 400,
        maxHeight: 400,
        closeButton: false,
        // Extend options with a function that returns content
        setContent: function (result) {
            // Create popup content here
            return result.properties.label;
        }
    }
    ...
});

This would allow you to also pass false (or falsy values) in place of options to disable popups entirely, or true (or truthy values) for "default" popup behavior.

Let me know what you think?