use the context’s document to create the input Event (#2169)

closes #2159

Author: Fil

src/plot.js

@@ -175,7 +175,7 @@ export function plot(options = {}) {
   context.dispatchValue = (value) => {
     if (figure.value === value) return;
     figure.value = value;
-    figure.dispatchEvent(new Event("input", {bubbles: true}));
+    figure.dispatchEvent(new context.document.defaultView.Event("input", {bubbles: true}));
   };
 
   // Reinitialize; for deriving channels dependent on other channels.

test/event-test.js

@@ -0,0 +1,8 @@
+import * as Plot from "@observablehq/plot";
+import * as assert from "assert";
+import {JSDOM} from "jsdom";
+
+it("Plot uses the context’s event", () => {
+  Plot.lineY([1, 2, 3], {tip: true}).plot({document: new JSDOM("").window.document});
+  assert.ok(true);
+});