Rename variables in setCapture proxy

The names of many variables were too similar. To make the code easier
to follow we renamed:

* _captureElem to _capturedElem
* _captureElemChanged() to _capturedElemChanged()
* captureElem to proxyElem
* elem to target

Co-authored-by: Alex Tanskanen <aleta@cendio.se>
Co-authored-by: Niko Lehto <nikle@cendio.se>

kasmweb/core/util/events.js

@@ -21,7 +21,7 @@ export function stopEvent(e) {
 
 // Emulate Element.setCapture() when not supported
 let _captureRecursion = false;
-let _captureElem = null;
+let _capturedElem = null;
 function _captureProxy(e) {
     // Recursion protection as we'll see our own event
     if (_captureRecursion) return;
@@ -30,7 +30,7 @@ function _captureProxy(e) {
     const newEv = new e.constructor(e.type, e);
 
     _captureRecursion = true;
-    _captureElem.dispatchEvent(newEv);
+    _capturedElem.dispatchEvent(newEv);
     _captureRecursion = false;
 
     // Avoid double events
@@ -48,58 +48,58 @@ function _captureProxy(e) {
 }
 
 // Follow cursor style of target element
-function _captureElemChanged() {
-    const captureElem = document.getElementById("noVNC_mouse_capture_elem");
-    captureElem.style.cursor = window.getComputedStyle(_captureElem).cursor;
+function _capturedElemChanged() {
+    const proxyElem = document.getElementById("noVNC_mouse_capture_elem");
+    proxyElem.style.cursor = window.getComputedStyle(_capturedElem).cursor;
 }
 
-const _captureObserver = new MutationObserver(_captureElemChanged);
+const _captureObserver = new MutationObserver(_capturedElemChanged);
 
 let _captureIndex = 0;
 
-export function setCapture(elem) {
-    if (elem.setCapture) {
+export function setCapture(target) {
+    if (target.setCapture) {
 
-        elem.setCapture();
+        target.setCapture();
 
         // IE releases capture on 'click' events which might not trigger
-        elem.addEventListener('mouseup', releaseCapture);
+        target.addEventListener('mouseup', releaseCapture);
 
     } else {
         // Release any existing capture in case this method is
         // called multiple times without coordination
         releaseCapture();
 
-        let captureElem = document.getElementById("noVNC_mouse_capture_elem");
+        let proxyElem = document.getElementById("noVNC_mouse_capture_elem");
 
-        if (captureElem === null) {
-            captureElem = document.createElement("div");
-            captureElem.id = "noVNC_mouse_capture_elem";
-            captureElem.style.position = "fixed";
-            captureElem.style.top = "0px";
-            captureElem.style.left = "0px";
-            captureElem.style.width = "100%";
-            captureElem.style.height = "100%";
-            captureElem.style.zIndex = 10000;
-            captureElem.style.display = "none";
-            document.body.appendChild(captureElem);
+        if (proxyElem === null) {
+            proxyElem = document.createElement("div");
+            proxyElem.id = "noVNC_mouse_capture_elem";
+            proxyElem.style.position = "fixed";
+            proxyElem.style.top = "0px";
+            proxyElem.style.left = "0px";
+            proxyElem.style.width = "100%";
+            proxyElem.style.height = "100%";
+            proxyElem.style.zIndex = 10000;
+            proxyElem.style.display = "none";
+            document.body.appendChild(proxyElem);
 
             // This is to make sure callers don't get confused by having
             // our blocking element as the target
-            captureElem.addEventListener('contextmenu', _captureProxy);
+            proxyElem.addEventListener('contextmenu', _captureProxy);
 
-            captureElem.addEventListener('mousemove', _captureProxy);
-            captureElem.addEventListener('mouseup', _captureProxy);
+            proxyElem.addEventListener('mousemove', _captureProxy);
+            proxyElem.addEventListener('mouseup', _captureProxy);
         }
 
-        _captureElem = elem;
+        _capturedElem = target;
         _captureIndex++;
 
         // Track cursor and get initial cursor
-        _captureObserver.observe(elem, {attributes: true});
-        _captureElemChanged();
+        _captureObserver.observe(target, {attributes: true});
+        _capturedElemChanged();
 
-        captureElem.style.display = "";
+        proxyElem.style.display = "";
 
         // We listen to events on window in order to keep tracking if it
         // happens to leave the viewport
@@ -114,7 +114,7 @@ export function releaseCapture() {
         document.releaseCapture();
 
     } else {
-        if (!_captureElem) {
+        if (!_capturedElem) {
             return;
         }
 
@@ -124,14 +124,14 @@ export function releaseCapture() {
             // Only clear it if it's the expected grab (i.e. no one
             // else has initiated a new grab)
             if (_captureIndex === expected) {
-                _captureElem = null;
+                _capturedElem = null;
             }
         }, 0, _captureIndex);
 
         _captureObserver.disconnect();
 
-        const captureElem = document.getElementById("noVNC_mouse_capture_elem");
-        captureElem.style.display = "none";
+        const proxyElem = document.getElementById("noVNC_mouse_capture_elem");
+        proxyElem.style.display = "none";
 
         window.removeEventListener('mousemove', _captureProxy);
         window.removeEventListener('mouseup', _captureProxy);