I'm trying to set a buffer with turfjs in a polygon. The polygon is loaded by L.geoJSON(); . When I execute bufferConcesion, this line var turfBuffer = turf.buffer(feature,value,{units:"kilometers"}); returns this error: Uncaught _u {} What might bethe problem.

This is my code:

    var featLayer = new L.GeoJSON(data, {
            weight: 1,
            fillOpacity: 0.7,
            color: 'red'
        onEachFeature: function(feature, layer) {

    function popUpBuffer(e){
        var id = e.target.feature.properties.id;
        var popup = L.popup()
            .setContent("<table><tr><td>Buffer (KM): </td><td><input type='text' id='buffer_value'><input type='hidden' id='ca_id' value='"+id+"'/></td><td><button onclick='bufferConcesion()'>Go</button></td></tr></table>")
    function bufferConcesion(){
        var value = document.getElementById("buffer_value").value;
            var layer = L.geoJSON(data,{
                onEachFeature: function(feature, layer) {
                    var turfBuffer = turf.buffer(feature,value,{units:"kilometers"});
                    var turfBufferLyr = L.geoJSON(turfBuffer, {style:{color:'yellow',dashArray:'5.5',fillOpacity:0}}).addTo(featLayer);

    function isID(feature){
        var id = document.getElementById("ca_id").value;
        if (feature.properties.id === id) return true
  • What does a feature look like if you log one, like console.log(feature) in your onEachFeature function?
    – Alex Leith
    Jan 12, 2018 at 2:24
  • like this: prntscr.com/hzaffe
    – tdaniel555
    Jan 12, 2018 at 3:42

1 Answer 1


Turf doesn't see Leaflet layers as GeoJSON. When I had roads as a leaflet layer this worked.

var buffered = turf.buffer(road.toGeoJSON(), 2, {units: 'miles'});

In your code try:

var turfBuffer = turf.buffer(feature.toGeoJSON(),value,{units:"kilometers"});

and see if it works.

  • Thank you Bill. I tried before with that code, but showed me another error: Uncaught TypeError: feature.toGeoJSON is not a function.
    – tdaniel555
    Jan 15, 2018 at 20:06
  • apparently it has to do with polygons. I copied a piece of code from turf (buffer a point) and pasted in my project and works fine. But then a changed to 'type':'Polygon' and added the coordinates and then returns Uncaught _u {}
    – tdaniel555
    Jan 15, 2018 at 20:13

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