From 46ec7d4d48391ff38a279bae9c92fdb162ba0343 Mon Sep 17 00:00:00 2001
From: Bob Zeleznik <zzzman@gmail.com>
Date: Mon, 18 May 2020 00:39:13 -0400
Subject: fixed some runtime errors with webbox

---
 src/client/views/nodes/WebBox.tsx | 26 +++++++++++++++-----------
 1 file changed, 15 insertions(+), 11 deletions(-)

(limited to 'src')

diff --git a/src/client/views/nodes/WebBox.tsx b/src/client/views/nodes/WebBox.tsx
index 82f05012a..b47fd2a53 100644
--- a/src/client/views/nodes/WebBox.tsx
+++ b/src/client/views/nodes/WebBox.tsx
@@ -48,11 +48,13 @@ export class WebBox extends ViewBoxAnnotatableComponent<FieldViewProps, WebDocum
     private _setPreviewCursor: undefined | ((x: number, y: number, drag: boolean) => void);
 
     iframeLoaded = action((e: any) => {
-        if (this._iframeRef.current?.contentDocument) {
-            this._iframeRef.current.contentDocument.addEventListener('pointerdown', this.iframedown, false);
-            this._iframeRef.current.contentDocument.addEventListener('scroll', this.iframeScrolled, false);
-            this.layoutDoc.scrollHeight = this._iframeRef.current.contentDocument.children?.[0].scrollHeight || 1000;
-            this._iframeRef.current.contentDocument.children[0].scrollTop = NumCast(this.layoutDoc.scrollTop);
+        const iframe = this._iframeRef.current;
+        if (iframe && iframe.contentDocument) {
+            iframe.setAttribute("enable-annotation", "true");
+            iframe.contentDocument.addEventListener('pointerdown', this.iframedown, false);
+            iframe.contentDocument.addEventListener('scroll', this.iframeScrolled, false);
+            this.layoutDoc.scrollHeight = iframe.contentDocument.children?.[0].scrollHeight || 1000;
+            iframe.contentDocument.children[0].scrollTop = NumCast(this.layoutDoc.scrollTop);
         }
         this._reactionDisposer?.();
         this._reactionDisposer = reaction(() => this.layoutDoc.scrollY,
@@ -77,8 +79,6 @@ export class WebBox extends ViewBoxAnnotatableComponent<FieldViewProps, WebDocum
 
         this.setURL();
 
-        this._iframeRef.current!.setAttribute("enable-annotation", "true");
-
         document.addEventListener("pointerup", this.onLongPressUp);
         document.addEventListener("pointermove", this.onLongPressMove);
         const field = Cast(this.rootDoc[this.props.fieldKey], WebField);
@@ -101,8 +101,8 @@ export class WebBox extends ViewBoxAnnotatableComponent<FieldViewProps, WebDocum
         this._reactionDisposer?.();
         document.removeEventListener("pointerup", this.onLongPressUp);
         document.removeEventListener("pointermove", this.onLongPressMove);
-        this._iframeRef.current!.contentDocument?.removeEventListener('pointerdown', this.iframedown);
-        this._iframeRef.current!.contentDocument?.removeEventListener('scroll', this.iframeScrolled);
+        this._iframeRef.current?.contentDocument?.removeEventListener('pointerdown', this.iframedown);
+        this._iframeRef.current?.contentDocument?.removeEventListener('scroll', this.iframeScrolled);
     }
 
     @action
@@ -362,8 +362,12 @@ export class WebBox extends ViewBoxAnnotatableComponent<FieldViewProps, WebDocum
                 style={{ pointerEvents: this.layoutDoc.isAnnotating && !this.layoutDoc.isBackground ? "all" : "none" }}
                 onWheel={e => e.stopPropagation()}
                 onScroll={e => {
-                    if (this._iframeRef.current!.contentDocument!.children[0].scrollTop !== this._outerRef.current!.scrollTop) {
-                        this._iframeRef.current!.contentDocument!.children[0].scrollTop = this._outerRef.current!.scrollTop;
+                    const iframe = this._iframeRef?.current?.contentDocument;
+                    const outerFrame = this._outerRef.current;
+                    if (iframe && outerFrame) {
+                        if (iframe.children[0].scrollTop !== outerFrame.scrollTop) {
+                            iframe.children[0].scrollTop = outerFrame.scrollTop;
+                        }
                     }
                     //this._outerRef.current!.scrollTop !== this._scrollTop && (this._outerRef.current!.scrollTop = this._scrollTop)
                 }}>
-- 
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