Add a "layers" parameter to "Evented#on"

[jfirebaugh]

Map events should accept an optional second parameter which is the name of a layer or an array of layer names for which to delegate events. Internally, this would bind an event handler that uses featuresAt and dispatches the event only when it matches features from the given layer(s). The features themselves would be passed as a member of the event object. For example:

map.on('click', 'poi', function(e) {
    (new Popup())
        .setLatLng(e.features[0].latLng)
        .setHTML(e.features[0].properties.description)
        .addTo(map);
});

This should not require setting interactive: true for each layer separately; binding a delegated event should automatically enable interactivity for the specified layers.

[mourner]

This should not require setting interactive: true for each layer separately; binding a delegated event should automatically enable interactivity for the specified layers.

This may be tricky, because you need to reparse tiles when interactive for a layer changes.

[lucaswoj]

We should do this as soon as #2224 lands

[arthurhammer]

Playing with v0.35 and pretty happy about this change. Any plans to support multiple layers to query with on?

[anandthakker]

Seems like a doable enhancement to me -- @jfirebaugh did you encounter any subtleties in implementing this that would make this problematic?

[mourner]

Looks like a one-line change to me since underlying queryRenderedFeatures already accepts an array of layer ids.

[jfirebaugh]

Yeah, should be straightforward. @arthurhammer can you open a new issue so we don't lose track of the request?

[arthurhammer]

Done in #4578. Thanks!