feat(axisPointer): trigger axisPointer when data is null (with echarts.connect)

src/component/axisPointer/AxisPointerModel.ts

@@ -89,6 +89,7 @@ class AxisPointerModel extends ComponentModel<AxisPointerOption> {
         snap: false,
         triggerTooltip: true,
         triggerEmphasis: true,
+        triggerOnNull: false,
 
         value: null,
         status: null, // Init value depends on whether handle is used.

src/component/axisPointer/axisTrigger.ts

@@ -166,13 +166,14 @@ export default function axisTrigger(
         each(coordSysAxesInfo.coordSysAxesInfo[coordSysKey], function (axisInfo, key) {
             const axis = axisInfo.axis;
             const inputAxisInfo = findInputAxisInfo(inputAxesInfo, axisInfo);
+            const triggerOnNull = axisInfo.triggerOnNull;
             // If no inputAxesInfo, no axis is restricted.
-            if (!shouldHide && coordSysContainsPoint && (!inputAxesInfo || inputAxisInfo)) {
+            if (triggerOnNull || (!shouldHide && coordSysContainsPoint && (!inputAxesInfo || inputAxisInfo))) {
                 let val = inputAxisInfo && inputAxisInfo.value;
                 if (val == null && !isIllegalPoint) {
                     val = axis.pointToData(point);
                 }
-                val != null && processOnAxis(axisInfo, val, updaters, false, outputPayload);
+                (triggerOnNull || val != null) && processOnAxis(axisInfo, val, updaters, false, outputPayload);
             }
         });
     });

src/component/axisPointer/modelHelper.ts

@@ -50,6 +50,7 @@ interface AxisInfo {
     axisPointerModel: Model<CommonAxisPointerOption>
     triggerTooltip: boolean
     triggerEmphasis: boolean
+    triggerOnNull: boolean
     involveSeries: boolean
     snap: boolean
     useHandle: boolean
@@ -89,6 +90,7 @@ export function collect(ecModel: GlobalModel, api: ExtensionAPI) {
          *      axisPointerModel,
          *      triggerTooltip,
          *      triggerEmphasis,
+         *      triggerOnNull,
          *      involveSeries,
          *      snap,
          *      seriesModels,
@@ -197,6 +199,7 @@ function collectAxesInfo(result: CollectionResult, ecModel: GlobalModel, api: Ex
 
             const snap = axisPointerModel.get('snap');
             const triggerEmphasis = axisPointerModel.get('triggerEmphasis');
+            const triggerOnNull = axisPointerModel.get('triggerOnNull');
             const axisKey = makeKey(axis.model);
             const involveSeries = triggerTooltip || snap || axis.type === 'category';
 
@@ -208,6 +211,7 @@ function collectAxesInfo(result: CollectionResult, ecModel: GlobalModel, api: Ex
                 axisPointerModel: axisPointerModel,
                 triggerTooltip: triggerTooltip,
                 triggerEmphasis: triggerEmphasis,
+                triggerOnNull: triggerOnNull,
                 involveSeries: involveSeries,
                 snap: snap,
                 useHandle: isHandleTrigger(axisPointerModel),

src/util/types.ts

@@ -1380,6 +1380,8 @@ export interface CommonAxisPointerOption {
 
     triggerEmphasis?: boolean
 
+    triggerOnNull?: boolean
+
     /**
      * current value. When using axisPointer.handle, value can be set to define the initial position of axisPointer.
      */