Experiment: add support for distinguishing hover & click events

src/interactions/pointer.js

@@ -126,7 +126,7 @@ function pointerK(kx, ky, {x, y, px, py, maxRadius = 40, channels, render, ...op
 
         // Dispatch the value. When simultaneously exiting this facet and
         // entering a new one, prioritize the entering facet.
-        if (!(i == null && facetState?.size > 1)) context.dispatchValue(i == null ? null : data[i]);
+        if (!(i == null && facetState?.size > 1)) context.dispatchValue(i == null ? null : data[i], s);
         return r;
       }
 

src/plot.js

@@ -2,18 +2,33 @@ import {creator, select} from "d3";
 import {createChannel, inferChannelScale} from "./channel.js";
 import {createContext} from "./context.js";
 import {createDimensions} from "./dimensions.js";
-import {createFacets, recreateFacets, facetExclude, facetGroups, facetTranslator, facetFilter} from "./facet.js";
+import {createFacets, facetExclude, facetFilter, facetGroups, facetTranslator, recreateFacets} from "./facet.js";
 import {pointer, pointerX, pointerY} from "./interactions/pointer.js";
 import {createLegends, exposeLegends} from "./legends.js";
 import {Mark} from "./mark.js";
 import {axisFx, axisFy, axisX, axisY, gridFx, gridFy, gridX, gridY} from "./marks/axis.js";
 import {frame} from "./marks/frame.js";
 import {tip} from "./marks/tip.js";
-import {isColor, isIterable, isNone, isScaleOptions} from "./options.js";
-import {arrayify, map, yes, maybeIntervalTransform, subarray} from "./options.js";
+import {
+  arrayify,
+  isColor,
+  isIterable,
+  isNone,
+  isScaleOptions,
+  map,
+  maybeIntervalTransform,
+  subarray,
+  yes
+} from "./options.js";
 import {createProjection, getGeometryChannels, hasProjection} from "./projection.js";
-import {createScales, createScaleFunctions, autoScaleRange, exposeScales} from "./scales.js";
-import {innerDimensions, outerDimensions} from "./scales.js";
+import {
+  autoScaleRange,
+  createScaleFunctions,
+  createScales,
+  exposeScales,
+  innerDimensions,
+  outerDimensions
+} from "./scales.js";
 import {isPosition, registry as scaleRegistry} from "./scales/index.js";
 import {applyInlineStyles, maybeClassName} from "./style.js";
 import {initializer} from "./transforms/basic.js";
@@ -172,10 +187,11 @@ export function plot(options = {}) {
   };
 
   // Allows e.g. the pointer transform to support viewof.
-  context.dispatchValue = (value) => {
-    if (figure.value === value) return;
+  context.dispatchValue = (value, sticky) => {
+    if (figure.value === value && context.stickyState === sticky) return;
     figure.value = value;
-    figure.dispatchEvent(new Event("input", {bubbles: true}));
+    context.stickyState = sticky;
+    figure.dispatchEvent(new StickyEvent("input", {bubbles: true, sticky}));
   };
 
   // Reinitialize; for deriving channels dependent on other channels.
@@ -743,3 +759,10 @@ function outerRange(scale) {
   if (x2 < x1) [x1, x2] = [x2, x1];
   return [x1, x2 + scale.bandwidth()];
 }
+
+class StickyEvent extends Event {
+  constructor(type, options) {
+    super(type, options);
+    this.sticky = options.sticky;
+  }
+}