Merge branch 'develop' into refactor/notification_settings

1 files changed, 26 insertions, 0 deletions

diff --git a/src/components/chat/chat_layout_utils.js b/src/components/chat/chat_layout_utils.js
new file mode 100644
index 00000000..609dc0c9
--- /dev/null
+++ b/src/components/chat/chat_layout_utils.js
@@ -0,0 +1,26 @@
+// Captures a scroll position
+export const getScrollPosition = (el) => {
+  return {
+    scrollTop: el.scrollTop,
+    scrollHeight: el.scrollHeight,
+    offsetHeight: el.offsetHeight
+  }
+}
+
+// A helper function that is used to keep the scroll position fixed as the new elements are added to the top
+// Takes two scroll positions, before and after the update.
+export const getNewTopPosition = (previousPosition, newPosition) => {
+  return previousPosition.scrollTop + (newPosition.scrollHeight - previousPosition.scrollHeight)
+}
+
+export const isBottomedOut = (el, offset = 0) => {
+  if (!el) { return }
+  const scrollHeight = el.scrollTop + offset
+  const totalHeight = el.scrollHeight - el.offsetHeight
+  return totalHeight <= scrollHeight
+}
+
+// Height of the scrollable container. The dynamic height is needed to ensure the mobile browser panel doesn't overlap or hide the posting form.
+export const scrollableContainerHeight = (inner, header, footer) => {
+  return inner.offsetHeight - header.clientHeight - footer.clientHeight
+}