signal-desktop/ts/components/conversation/media-gallery/groupMessagesByDate.ts

/**
 * @prettier
 */
import moment from 'moment';
import { compact, groupBy, sortBy } from 'lodash';

import { Message } from './propTypes/Message';

export const groupMessagesByDate = (
  timestamp: number,
  messages: Array<Message>
): any => {
  const referenceDateTime = moment.utc(timestamp);
  const today = moment(referenceDateTime).startOf('day');
  const yesterday = moment(referenceDateTime)
    .subtract(1, 'day')
    .startOf('day');
  const thisWeek = moment(referenceDateTime).startOf('isoWeek');
  const thisMonth = moment(referenceDateTime).startOf('month');

  const sorted = sortBy(messages, message => -message.received_at);
  const annotations = sorted.map(message => {
    const date = moment.utc(message.received_at);

    if (date.isAfter(today)) {
      return {
        order: 0,
        label: 'today',
        message,
      };
    } else if (date.isAfter(yesterday)) {
      return {
        order: 1,
        label: 'yesterday',
        message,
      };
    } else if (date.isAfter(thisWeek)) {
      return {
        order: 2,
        label: 'thisWeek',
        message,
      };
    } else if (date.isAfter(thisMonth)) {
      return {
        order: 3,
        label: 'thisMonth',
        message,
      };
    }

    return {
      order: date.year() * 100 + date.month(),
      label: 'yearMonth',
      message,
    };
  });

  return groupBy(annotations, 'label');
};