From 6847cf47916b99b573e4a49b083dec937f10c83a Mon Sep 17 00:00:00 2001
From: Alexander Marks <aomarks@google.com>
Date: Thu, 2 Aug 2018 14:58:07 -0700
Subject: [PATCH] Make Polymer gestures library safe for Closure property
 renaming (take 2). (#5314)

Make Polymer gestures library safe for Closure property renaming.

The issue here was that we were assuming that the method for a given
gesture would always match the string name of that gesture, e.g. that if
the gesture name was "mousedown" that we could call
gestureDefinition.mousedown. In actuality, gestureDefinition.mousedown
could be renamed by Closure, which would throw with "undefined is not a
function".

The fix is to move the GesturesRecognizer type into our externs, which
prevents those methods from being renamed.
---
 externs/polymer-internal-shared-types.js | 48 ++++++++++++++++++++++++
 lib/utils/gestures.js                    | 47 ++---------------------
 2 files changed, 51 insertions(+), 44 deletions(-)

diff --git a/externs/polymer-internal-shared-types.js b/externs/polymer-internal-shared-types.js
index 937ba617ed..fd954c1180 100644
--- a/externs/polymer-internal-shared-types.js
+++ b/externs/polymer-internal-shared-types.js
@@ -164,3 +164,51 @@ function AsyncInterface(){}
 AsyncInterface.prototype.run;
 /** @type {function(number): void} */
 AsyncInterface.prototype.cancel;
+
+/** @record */
+let GestureInfo = function(){};
+/** @type {string|undefined} */
+GestureInfo.prototype.state;
+/** @type {boolean|undefined} */
+GestureInfo.prototype.started;
+/** @type {!Array<?>|undefined} */
+GestureInfo.prototype.moves;
+/** @type {number|undefined} */
+GestureInfo.prototype.x;
+/** @type {number|undefined} */
+GestureInfo.prototype.y;
+/** @type {boolean|undefined} */
+GestureInfo.prototype.prevent;
+/** @type {function(?): void|undefined} */
+GestureInfo.prototype.addMove;
+/** @type {null|undefined} */
+GestureInfo.prototype.movefn;
+/** @type {null|undefined} */
+GestureInfo.prototype.upFn;
+
+/** @record */
+let GestureRecognizer = function(){};
+/** @type {string} */
+GestureRecognizer.prototype.name;
+/** @type {!Array<string>} */
+GestureRecognizer.prototype.deps;
+/** @type {function(): void} */
+GestureRecognizer.prototype.reset;
+/** @type {function(MouseEvent): void | undefined} */
+GestureRecognizer.prototype.mousedown;
+/** @type {(function(MouseEvent): void | undefined)} */
+GestureRecognizer.prototype.mousemove;
+/** @type {(function(MouseEvent): void | undefined)} */
+GestureRecognizer.prototype.mouseup;
+/** @type {(function(TouchEvent): void | undefined)} */
+GestureRecognizer.prototype.touchstart;
+/** @type {(function(TouchEvent): void | undefined)} */
+GestureRecognizer.prototype.touchmove;
+/** @type {(function(TouchEvent): void | undefined)} */
+GestureRecognizer.prototype.touchend;
+/** @type {(function(MouseEvent): void | undefined)} */
+GestureRecognizer.prototype.click;
+/** @type {!GestureInfo} */
+GestureRecognizer.prototype.info;
+/** @type {!Array<string>} */
+GestureRecognizer.prototype.emits;
diff --git a/lib/utils/gestures.js b/lib/utils/gestures.js
index 9b0548bf4d..c2a93270a1 100644
--- a/lib/utils/gestures.js
+++ b/lib/utils/gestures.js
@@ -92,50 +92,6 @@ function PASSIVE_TOUCH(eventName) {
 // Check for touch-only devices
 let IS_TOUCH_ONLY = navigator.userAgent.match(/iP(?:[oa]d|hone)|Android/);
 
-/** @record */
-const GestureInfo = function(){}; // eslint-disable-line no-unused-vars
-/** @type {string|undefined} */
-GestureInfo.prototype.state;
-/** @type {boolean|undefined} */
-GestureInfo.prototype.started;
-/** @type {!Array<?>|undefined} */
-GestureInfo.prototype.moves;
-/** @type {number|undefined} */
-GestureInfo.prototype.x;
-/** @type {number|undefined} */
-GestureInfo.prototype.y;
-/** @type {boolean|undefined} */
-GestureInfo.prototype.prevent;
-/** @type {function(?): void|undefined} */
-GestureInfo.prototype.addMove;
-/** @type {null|undefined} */
-GestureInfo.prototype.movefn;
-/** @type {null|undefined} */
-GestureInfo.prototype.upFn;
-
-/** @record */
-const GestureRecognizer = function(){}; // eslint-disable-line no-unused-vars
-/** @type {function(): void} */
-GestureRecognizer.prototype.reset;
-/** @type {function(MouseEvent): void | undefined} */
-GestureRecognizer.prototype.mousedown;
-/** @type {(function(MouseEvent): void | undefined)} */
-GestureRecognizer.prototype.mousemove;
-/** @type {(function(MouseEvent): void | undefined)} */
-GestureRecognizer.prototype.mouseup;
-/** @type {(function(TouchEvent): void | undefined)} */
-GestureRecognizer.prototype.touchstart;
-/** @type {(function(TouchEvent): void | undefined)} */
-GestureRecognizer.prototype.touchmove;
-/** @type {(function(TouchEvent): void | undefined)} */
-GestureRecognizer.prototype.touchend;
-/** @type {(function(MouseEvent): void | undefined)} */
-GestureRecognizer.prototype.click;
-/** @type {!GestureInfo} */
-GestureRecognizer.prototype.info;
-/** @type {!Array<string>} */
-GestureRecognizer.prototype.emits;
-
 // keep track of any labels hit by the mouseCanceller
 /** @type {!Array<!HTMLLabelElement>} */
 const clickedLabels = [];
@@ -378,7 +334,10 @@ function untrackDocument(stateObj) {
 // Use passive event listeners, if supported, to not affect scrolling performance
 document.addEventListener('touchend', ignoreMouse, SUPPORTS_PASSIVE ? {passive: true} : false);
 
+/** @type {!Object<string, !GestureRecognizer>} */
 export const gestures = {};
+
+/** @type {!Array<!GestureRecognizer>} */
 export const recognizers = [];
 
 /**