vesting-schedule.js

'use strict';

const _ = require('lodash');
const moment = require('moment');

function cliff(months, cliffMonths, totalMonths) {
  return (months < cliffMonths) ? 0 : Math.min(1, months / totalMonths);
};

module.exports = {
  computeVestStats(grants, atDate) {
    // Unrolled for speed.
    const stats = { numShares: 0, date: atDate };

    for (let i = 0; i < grants.length; i++) {
      const grant = grants[i];
      const amount = Math.floor(cliff(atDate.diff(grant.date, 'months'), grant.cliffYears * 12, grant.totalYears * 12) * grant.amount);
      stats.numShares += amount;
    }

    return stats;
  },

  lastActiveDate(grants) {
    return _.max(_.map(grants, g => {
      return moment(g.date).add(g.totalYears, 'years');
    }));
  }
};

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