PDOKGeocoder.js

var PDOKGeocoder = L.Class.extend({
    options: {
        suggestUrl: 'https://geodata.nationaalgeoregister.nl/locatieserver/v3/suggest',
        lookupUrl: 'https://geodata.nationaalgeoregister.nl/locatieserver/v3/lookup',
        geocodingQueryParams: {
            wt: 'json'
        }
    },

    initialize: function(options) {
        L.Util.setOptions(this, options);
    },

    geocode: function(value, callback, context) {
        var query = L.Util.extend({}, this.options.geocodingQueryParams, {'q': value});
        fetchJSON(this.options.suggestUrl + L.Util.getParamString(query), function(response) {
            var results = response.response.docs.map(function(doc) {
                return {
                    id: doc.id,
                    name: doc.weergavenaam,
                };
            });

            callback.call(context, results);
        });
    },

    lookup: function(id, callback, context) {
        fetchJSON(this.options.lookupUrl + L.Util.getParamString({id: id}), function(response) {
            var wkt = response.response.docs[0].centroide_ll;
            var match = wkt.match(/POINT\((\d+(?:\.\d+)?)\s+(\d+(?:\.\d+)?)\)/);
            callback.call(context, [parseFloat(match[2], 10), parseFloat(match[1], 10)]);
        });
    }
});