signal-desktop/ts/components/conversation/ScrollDownButton.tsx

import React from 'react';
import classNames from 'classnames';

import { LocalizerType } from '../../types/Util';

export type Props = {
  withNewMessages: boolean;
  conversationId: string;

  scrollDown: (conversationId: string) => void;

  i18n: LocalizerType;
};

export class ScrollDownButton extends React.Component<Props> {
  public render() {
    const { conversationId, withNewMessages, i18n, scrollDown } = this.props;
    const altText = withNewMessages
      ? i18n('messagesBelow')
      : i18n('scrollDown');

    return (
      <div className="module-scroll-down">
        <button
          className={classNames(
            'module-scroll-down__button',
            withNewMessages ? 'module-scroll-down__button--new-messages' : null
          )}
          onClick={() => {
            scrollDown(conversationId);
          }}
          title={altText}
        >
          <div className="module-scroll-down__icon" />
        </button>
      </div>
    );
  }
}