Add back scroll position after height change

1 files changed, 11 insertions, 0 deletions

diff --git a/app/src/web/ts/auto_resize_textarea.ts b/app/src/web/ts/auto_resize_textarea.ts
index 1f1b3613..c71a75a1 100644
--- a/app/src/web/ts/auto_resize_textarea.ts
+++ b/app/src/web/ts/auto_resize_textarea.ts
@@ -12,8 +12,19 @@
         // If no height is defined, have min bound to current height;
         // otherwise we will allow for height decreases in case user deletes text
         const minHeight = parseInt(el.getAttribute(dataAttribute) ?? '0');
+
+        // Save scroll position prior to height update
+        // See https://stackoverflow.com/a/18262927/4407321
+        const scrollLeft = window.pageXOffset ||
+        (document.documentElement || document.body.parentNode || document.body).scrollLeft;
+        const scrollTop  = window.pageYOffset ||
+        (document.documentElement || document.body.parentNode || document.body).scrollTop;
+
         el.style.height = 'inherit';
         el.style.height = `${Math.max(el.scrollHeight, minHeight)}px`;
+
+        // Go to original scroll position
+        window.scrollTo(scrollLeft, scrollTop);
     };
     function _frostExpandAll() {
         textareas.forEach(_frostAutoExpand);