JavaScript回调中的冒号

Question

I'm using the data layer on google maps with point geometries that occasionally use the same coordinates. To access all of the features at a given coordinate I'm trying to use a port of OverlappingMarkerSpiderfier for the data layer instead of markers called OverlappingFeatureSpiderfier .

I'm have problems adding the click handler for the data layer. In the documentation it calls for:

ofs.addListener("click", function(event: google.maps.Data.MouseEvent) {
  var theFeatureThatWasClicked = event.feature;
}

Besides the missing parenthesis, I can't figure out what's going on with that colon in the callback. Any ideas?

Answer 1

The colon syntax there is a TypeScript type annotation.

To use that with vanilla JS, just put function(event) .