derma/src/logic.js

const { pathOr, hasPath } = require('ramda');
const parseArgs = require('minimist');
const process = require('process');

const event_url = (event_id) => `https://www.facebook.com/events/${event_id}`;

const page_url = (page_id) => `https://www.facebook.com/${page_id}`;

const page_events_url = (page_id) => page_url(page_id) + '/events/';

export const parse_args = (args) => {
  const argv = parseArgs(args);

  const has_help_param =
    hasPath(['h'], argv) || hasPath(['help'], argv) || hasPath(['?'], argv);
  if (has_help_param) {
    process.exit(1);
  }

  const away_empty_strings = (str) => str.length !== 0;
  const page_id_to_page_events_url = page_events_url;
  const parse_param = (param) =>
    pathOr('', [param], argv)
      .split(',')
      .filter(away_empty_strings)
      .map(page_id_to_page_events_url);

  const events = pathOr(null, ['events'], argv);

  return {
    page_ids: [
      ...parse_param('page'),
      ...parse_param('p'),
      ...parse_param('pages'),
    ],
    events,
  };
};