move logic to preventParentScroll util function

src/autocomplete.js

@@ -10,6 +10,7 @@ var dom = require("./lib/dom");
 var snippetManager = require("./snippets").snippetManager;
 var config = require("./config");
 var event = require("./lib/event");
+var preventParentScroll = require("./lib/scroll").preventParentScroll;
 
 /**
  * @typedef BaseCompletion
@@ -587,13 +588,7 @@ class Autocomplete {
             this.tooltipNode.id = "doc-tooltip";
             this.tooltipNode.setAttribute("role", "tooltip");
             // prevent editor scroll if tooltip is inside an editor
-            this.tooltipNode.addEventListener("wheel", function(event) {
-                event.stopPropagation();
-                var contentOverflows = this.tooltipNode.scrollHeight > this.tooltipNode.clientHeight;
-                if (!contentOverflows) {
-                    event.preventDefault();
-                }
-            }.bind(this));
+            this.tooltipNode.addEventListener("wheel", preventParentScroll);
         }
         var theme = this.editor.renderer.theme;
         this.tooltipNode.className = "ace_tooltip ace_doc-tooltip " +

src/lib/scroll.js

@@ -0,0 +1,8 @@
+exports.preventParentScroll = function preventParentScroll(event) {
+    event.stopPropagation();
+    var target = event.currentTarget;
+    var contentOverflows = target.scrollHeight > target.clientHeight;
+    if (!contentOverflows) {
+        event.preventDefault();
+    }
+};

src/tooltip.js

@@ -3,6 +3,7 @@
 var dom = require("./lib/dom");
 var event = require("./lib/event");
 var Range = require("./range").Range;
+var preventParentScroll = require("./lib/scroll").preventParentScroll;
 
 var CLASSNAME = "ace_tooltip";
 
@@ -191,13 +192,7 @@ class HoverTooltip extends Tooltip {
             if (!el.contains(document.activeElement)) this.hide();
         }.bind(this));
 
-        el.addEventListener("wheel", function(event) {
-            event.stopPropagation();
-            var contentOverflows = el.scrollHeight > el.clientHeight;
-            if (!contentOverflows) {
-                event.preventDefault();
-            }
-        });
+        el.addEventListener("wheel", preventParentScroll);
     }
 
     addToEditor(editor) {