From 718fba7a1f2900d8e7354eed596ff5cc13cc8179 Mon Sep 17 00:00:00 2001
From: Michael Barry <msbarry@users.noreply.github.com>
Date: Thu, 11 Jul 2019 09:40:05 -0400
Subject: [PATCH] Add check for startPos to fix #7864 (#8462)

* Add check for startPos to fix #7864

* add test
---
 src/ui/bind_handlers.js           |  2 +-
 test/unit/ui/map_events.test.js   | 18 +++++++++++++++++-
 test/util/simulate_interaction.js |  2 +-
 3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/src/ui/bind_handlers.js b/src/ui/bind_handlers.js
index 9ed7c877ab4..b66144ffd1f 100644
--- a/src/ui/bind_handlers.js
+++ b/src/ui/bind_handlers.js
@@ -152,7 +152,7 @@ export default function bindHandlers(map: Map, options: {interactive: boolean, c
 
     function onClick(e: MouseEvent) {
         const pos = DOM.mousePos(el, e);
-        if (pos.equals(startPos) || pos.dist(startPos) < options.clickTolerance) {
+        if (!startPos || pos.equals(startPos) || pos.dist(startPos) < options.clickTolerance) {
             map.fire(new MapMouseEvent('click', map, e));
         }
     }
diff --git a/test/unit/ui/map_events.test.js b/test/unit/ui/map_events.test.js
index 42d783fc3f8..c836e982277 100644
--- a/test/unit/ui/map_events.test.js
+++ b/test/unit/ui/map_events.test.js
@@ -1,6 +1,6 @@
 import { test } from '../../util/test';
 import { createMap } from '../../util';
-import simulate from '../../util/simulate_interaction';
+import simulate, { window } from '../../util/simulate_interaction';
 
 test('Map#on adds a non-delegated event listener', (t) => {
     const map = createMap(t);
@@ -585,3 +585,19 @@ test(`Map#on mousedown does not fire subsequent click event if mouse position ch
     map.remove();
     t.end();
 });
+
+test(`Map#on click fires subsequent click event if there is no corresponding mousedown/mouseup event`, (t) => {
+    const map = createMap(t, { clickTolerance: 4 });
+
+    const click = t.spy();
+    map.on('click', click);
+    const canvas = map.getCanvas();
+
+    const MouseEvent = window(canvas).MouseEvent;
+    const event = new MouseEvent('click', {bubbles: true, clientX: 100, clientY: 100});
+    canvas.dispatchEvent(event);
+    t.ok(click.called);
+
+    map.remove();
+    t.end();
+});
diff --git a/test/util/simulate_interaction.js b/test/util/simulate_interaction.js
index c800a0be84a..b85479ae7f8 100644
--- a/test/util/simulate_interaction.js
+++ b/test/util/simulate_interaction.js
@@ -1,5 +1,5 @@
 
-function window(target) {
+export function window(target) {
     if (target.ownerDocument) {
         return target.ownerDocument.defaultView;
     } else if (target.defaultView) {