fix(subchart): fix subchart esm import failure

Move .unbindZoomEvent() from zoom.ts --> interaction.ts

Fix #2255

src/ChartInternal/interactions/interaction.ts

@@ -244,5 +244,20 @@ export default {
 
 	setDragStatus(isDragging: boolean): void {
 		this.state.dragging = isDragging;
+	},
+
+	/**
+	 * Unbind zoom events
+	 * @private
+	 */
+	unbindZoomEvent(): void {
+		const $$ = this;
+		const {$el: {eventRect, zoomResetBtn}} = $$;
+
+		eventRect
+			.on(".zoom", null)
+			.on(".drag", null);
+
+		zoomResetBtn?.style("display", "none");
 	}
 };

src/ChartInternal/interactions/zoom.ts

@@ -41,21 +41,6 @@ export default {
 		}
 	},
 
-	/**
-	 * Unbind zoom events
-	 * @private
-	 */
-	unbindZoomEvent(): void {
-		const $$ = this;
-		const {$el: {eventRect, zoomResetBtn}} = $$;
-
-		eventRect
-			.on(".zoom", null)
-			.on(".drag", null);
-
-		zoomResetBtn?.style("display", "none");
-	},
-
 	/**
 	 * Generate zoom
 	 * @private

test/esm/subchart-spec.ts

@@ -0,0 +1,33 @@
+/**
+ * Copyright (c) 2017 ~ present NAVER Corp.
+ * billboard.js project is licensed under the MIT license
+ */
+/* eslint-disable */
+/* global describe, beforeEach, it, expect */
+import {expect} from "chai";
+import bb, {line, subchart} from "../../src/index.esm";
+
+describe("ESM subchart", function() {
+    let chart;
+
+    const args: any = {
+        data: {
+            columns: [
+                ["data1", 30, 350, 300, 0, 100],
+                ["data2", 200, 100, 140, 200, 150]
+            ],
+            type: line()
+        },
+        subchart: {
+            enabled: subchart()
+        }
+    };
+
+	beforeEach(() => {
+		chart = bb.generate(args);
+	});
+
+    it("shouldn't throw error during zoom", () => {
+        expect(chart.subchart.show()).to.not.throw;
+    });
+});