pre-validate reverse coordinates to avoid v6 4xx response

Author: mpothier

lib/index.js

@@ -675,13 +675,21 @@ MapboxGeocoder.prototype = {
     switch (requestType) {
     case GEOCODE_REQUEST_TYPE.REVERSE: {
       // expected to be coordinates in the form `lat, lon`
-      var coords = search.split(spacesOrCommaRgx).map(function(c) {
+      var coords = search.trim().split(spacesOrCommaRgx).map(function(c) {
         return parseFloat(c, 10);
       })
       if (!self.options.flipCoordinates) {
+        // flip order to `lon, lat`
         coords.reverse();
       }
 
+      // validate coordinates in range before proceeding
+      if (coords[0] < -180 || coords[0] > 180) {
+        throw new Error('Longitude out of range');
+      } else if (coords[1] < -90 || coords[1] > 90) {
+        throw new Error('Latitude out of range');
+      }
+
       config = extend(config,
         this.options.version === 'v6' ? { longitude: coords[0], latitude: coords[1]} : { query: coords },
         {limit: 1 }
@@ -725,7 +733,18 @@ MapboxGeocoder.prototype = {
     this._eventEmitter.emit('loading', { query: searchInput });
 
     const requestType = this._requestType(this.options, searchInput);
-    const config = this._setupConfig(requestType, searchInput);
+    
+    let 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();
+    }
 
     var request;
     switch (requestType) {
@@ -942,6 +961,11 @@ MapboxGeocoder.prototype = {
     var errorMessage = "<div class='mapbox-gl-geocoder--error'>There was an error reaching the server</div>"
     this._renderMessage(errorMessage);
   },
+  
+  _renderCustomError: function(message){
+    var errorMessage = `<div class='mapbox-gl-geocoder--error'>${message}</div>`
+    this._renderMessage(errorMessage);
+  },
 
   _renderLocationError: function(){
     var errorMessage = "<div class='mapbox-gl-geocoder--error'>A location error has occurred</div>"