fix promise resolution

Author: mpothier

lib/index.js

@@ -735,16 +735,35 @@ MapboxGeocoder.prototype = {
 
     const requestType = this._requestType(this.options, searchInput);
 
-    let config;
+    var config;
     // setup request parameters config and pre-validate values
     try {
       config = this._setupConfig(requestType, searchInput);
     } catch (err) {
-      this._hideLoadingIcon();
-      this._hideAttribution();
-      this._typeahead.selected = null;
-      this._renderCustomError(err.message);
-      return Promise.resolve();
+      const request = new Promise(function (resolve) {
+        resolve();
+      });
+      request.then(function() {
+        return {
+          type: 'FeatureCollection',
+          features: [],
+          config
+        }
+      }.bind(this))
+        .then(function(){
+          this._hideLoadingIcon();
+          this._hideAttribution();
+          this._typeahead.selected = null;
+          this._renderCustomError(err.message);
+          this._eventEmitter.emit('results', {
+            type: 'FeatureCollection',
+            features: [],
+            config
+          });
+          this._eventEmitter.emit('error', { error: err });
+
+        }.bind(this))
+      return request
     }
 
     var request;