From 63020feb8e26d9d227d445a31bd8e27adf995d52 Mon Sep 17 00:00:00 2001
From: mertsincan <sincan.mert@gmail.com>
Date: Sun, 27 Sep 2020 18:27:08 +0300
Subject: [PATCH] Fixed #500 - Improvement in behavior of components that have
 overlay panels in scrollable containers

---
 .../utils/ConnectedOverlayScrollHandler.js    | 39 ++++++++++++++++
 src/components/utils/DomHandler.js            | 46 +++++++++++++++++--
 2 files changed, 80 insertions(+), 5 deletions(-)
 create mode 100644 src/components/utils/ConnectedOverlayScrollHandler.js

diff --git a/src/components/utils/ConnectedOverlayScrollHandler.js b/src/components/utils/ConnectedOverlayScrollHandler.js
new file mode 100644
index 000000000..794cc83bc
--- /dev/null
+++ b/src/components/utils/ConnectedOverlayScrollHandler.js
@@ -0,0 +1,39 @@
+import DomHandler from './DomHandler';
+import UniqueComponentId from './UniqueComponentId';
+
+export default class ConnectedOverlayScrollHandler {
+
+    constructor(element, elementId = UniqueComponentId(), listener = () => {}) {
+        this.element = element;
+        this.elementId = elementId;
+        this.listener = listener;
+    }
+
+    bindScrollListener() {
+        this.scrollableParents = DomHandler.getScrollableParents(this.element);
+        this.scrollListeners = {};
+        for (let i = 0; i < this.scrollableParents.length; i++) {
+            let parent = this.scrollableParents[i];
+            let namespace = `${this.elementId}_${i}`;
+
+            if (!this.scrollListeners[namespace]) {
+                this.scrollListeners[namespace] = this.listener;
+                parent.addEventListener('scroll', this.scrollListeners[namespace]);
+            }
+        }
+    }
+
+    unbindScrollListener() {
+        if (this.scrollableParents) {
+            for (let i = 0; i < this.scrollableParents.length; i++) {
+                let parent = this.scrollableParents[i];
+                let namespace = `${this.elementId}_${i}`;
+
+                if (this.scrollListeners[namespace]) {
+                    parent.removeEventListener('scroll', this.scrollListeners[namespace]);
+                    this.scrollListeners[namespace] = null;
+                }
+            }
+        }
+    }
+}
diff --git a/src/components/utils/DomHandler.js b/src/components/utils/DomHandler.js
index 4dc91dfd8..e7eeaebe8 100755
--- a/src/components/utils/DomHandler.js
+++ b/src/components/utils/DomHandler.js
@@ -245,6 +245,42 @@ export default class DomHandler {
         element.style.left = left + 'px';
     }
 
+    static getParents(element, parents = []) {
+        return element['parentNode'] === null ? parents : this.getParents(element.parentNode, parents.concat([element.parentNode]));
+    }
+
+    static getScrollableParents(element) {
+        let scrollableParents = [];
+
+        if (element) {
+            let parents = this.getParents(element);
+            const overflowRegex = /(auto|scroll)/;
+            const overflowCheck = (node) => {
+                let styleDeclaration = window['getComputedStyle'](node, null);
+                return overflowRegex.test(styleDeclaration.getPropertyValue('overflow')) || overflowRegex.test(styleDeclaration.getPropertyValue('overflowX')) || overflowRegex.test(styleDeclaration.getPropertyValue('overflowY'));
+            };
+
+            for (let parent of parents) {
+                let scrollSelectors = parent.nodeType === 1 && parent.dataset['scrollselectors'];
+                if (scrollSelectors) {
+                    let selectors = scrollSelectors.split(',');
+                    for (let selector of selectors) {
+                        let el = this.findSingle(parent, selector);
+                        if (el && overflowCheck(el)) {
+                            scrollableParents.push(el);
+                        }
+                    }
+                }
+
+                if (parent.nodeType === 9 || overflowCheck(parent)) {
+                    scrollableParents.push(parent);
+                }
+            }
+        }
+
+        return scrollableParents;
+    }
+
     static getHiddenElementOuterHeight(element) {
         element.style.visibility = 'hidden';
         element.style.display = 'block';
@@ -423,10 +459,10 @@ export default class DomHandler {
     }
 
     static getFocusableElements(element) {
-        let focusableElements = DomHandler.find(element, `button:not([tabindex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden]), 
-                [href][clientHeight][clientWidth]:not([tabindex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden]), 
-                input:not([tabindex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden]), select:not([tabindex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden]), 
-                textarea:not([tabindex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden]), [tabIndex]:not([tabIndex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden]), 
+        let focusableElements = DomHandler.find(element, `button:not([tabindex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden]),
+                [href][clientHeight][clientWidth]:not([tabindex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden]),
+                input:not([tabindex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden]), select:not([tabindex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden]),
+                textarea:not([tabindex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden]), [tabIndex]:not([tabIndex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden]),
                 [contenteditable]:not([tabIndex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden])`
             );
 
@@ -449,4 +485,4 @@ export default class DomHandler {
                 this.hasClass(element.parentElement, 'p-checkbox') || this.hasClass(element.parentElement, 'p-radiobutton')
         );
     }
-}
\ No newline at end of file
+}