Method componentDidUpdate

web/chat/chat-message-list.react.js:120–164

(prevProps: Props, prevState: State, snapshot: ?Snapshot)

  }

  componentDidUpdate(prevProps: Props, prevState: State, snapshot: ?Snapshot) {
    const { messageListData } = this.props;
    const prevMessageListData = prevProps.messageListData;

    const { messageContainer } = this;
    if (
      messageContainer &&
      prevMessageListData !== messageListData &&
      messageContainer.scrollTop === 0
    ) {
      this.onScroll();
    }

    // We'll scroll to the bottom if the user was already scrolled to the bottom
    // before the new message, or if the new message was composed locally
    const hasNewMessage = ChatMessageList.hasNewMessage(this.props, prevProps);
    if (
      this.props.activeChatThreadID !== prevProps.activeChatThreadID ||
      (hasNewMessage &&
        messageListData &&
        messageListData[0].itemType === 'message' &&
        messageListData[0].messageInfoType === 'composable' &&
        messageListData[0].messageInfo.localID) ||
      (hasNewMessage &&
        snapshot &&
        Math.abs(snapshot.scrollTop) <= 1 &&
        !this.props.isEditState)
    ) {
      this.scrollToBottom();
    } else if (hasNewMessage && messageContainer && snapshot) {
      const { scrollTop, scrollHeight } = messageContainer;
      if (
        scrollHeight > snapshot.scrollHeight &&
        scrollTop === snapshot.scrollTop
      ) {
        const newHeight = scrollHeight - snapshot.scrollHeight;
        const newScrollTop = Math.abs(scrollTop) + newHeight;
        if (supportsReverseFlex) {
          messageContainer.scrollTop = -1 * newScrollTop;
        } else {
          messageContainer.scrollTop = newScrollTop;
        }
      }
    }
  }

  scrollToBottom() {
    if (this.messageContainer) {