jmeas/consecutive-segments.js

import _ from 'underscore';
import moment from 'moment';

// Segment an array of events by scale
var consecutiveSegments = function(segments, scale='weeks') {
  if (_.isEmpty(segments)) { return []; }

  let currentGroup = 0, currentMoment, prevMoment;
  return _.chain(segments)
    .map((events, timestamp) => {
      return { timestamp, events };
    })
    .reduce((memo, s, index, segments) => {

      // Check to see if the current group is the same
      // as the previous group by computing the difference
      // in their timestamps. They aren't consecutive when
      // the difference is > 1
      if (index) {
        currentMoment = moment.unix(s.timestamp).utc();
        prevMoment = moment.unix(segments[index - 1].timestamp).utc();
        if (currentMoment.diff(prevMoment, scale) > 1) {
          currentGroup++;
        }
      }

      // Ensure that the group exists, then push to it
      if (!memo[currentGroup]) {
        memo[currentGroup] = [];
      }
      memo[currentGroup].push(_.clone(s));
      return memo;
    }, [])
    .value();
};

export default consecutiveSegments;