Question

I have found similar questions about creating functions with optional parameters. But I continually run into errors is the parameter may not exist. I have an interactive map that is doing a bunch of things. However if outputlayer is null, the function will not execute. This layer may or may not exist. I just can’t seem to figure out how to pass this optional parameter in if it doesn’t exist. Thanks for any help!

function appdelete(selected,vectorlayer,drawFeature,outputlayer) {

    $(selected).prev().children().children().eq(2).val('Latitude');
    $(selected).prev().children().children().eq(4).val('Longitude');
    vectorlayer.destroyFeatures();
    drawFeature.activate();

    try {
        map.removeLayer(outputlayer);
    } catch(err) { };
}

Answer 1

Check if it exists first and maybe the type.

if(outputlayer && "object" === typeof outputlayer) {
    map.removeLayer(outputlayer);
}