zoomin protected method

src/index.ts

@@ -31,6 +31,7 @@ import { palette } from './colors';
 import * as d3 from 'd3';
 
 import debounce from 'lodash/debounce';
+import { AxisRange } from './types';
 
 
 const DEFAULT_TICK_SIZE = 2;
@@ -798,8 +799,7 @@ abstract class ChartwerkPod<T extends Serie, O extends Options> {
         this.state.yValueRange = yRange;
         this.brushStartSelection = null;
     }
-
-    this.options.callbackZoomIn([xRange, yRange]);
+    this.zoomIn([xRange, yRange]);
   }
 
   protected zoomOut(): void {
@@ -812,6 +812,13 @@ abstract class ChartwerkPod<T extends Serie, O extends Options> {
     this.options.callbackZoomOut(centers);
   }
 
+  protected zoomIn(ranges: AxisRange[]): void {
+    if(ranges === undefined) {
+      return;
+    }
+    this.options.callbackZoomIn(ranges);
+  }
+
   getAxisTicksFormatter(axisOptions: AxisOption): (d: any, i: number) => any {
     // TODO: ticksCount === 0 -> suspicious option
     if(axisOptions.ticksCount === 0) {