sum(values)

function main() {
  // Helper aggregation functions
  const sum = (arr) => arr.reduce((sum, x) => sum + x, 0);
  const count = (arr) => arr.length;
  const countDistinct = (arr) => new Set(arr).size;
  const min = (arr) => Math.min(...arr);
  const max = (arr) => Math.max(...arr);
  const avg = (arr) => count(arr)>0?(sum(arr)/count(arr)):0;
  const percentile = (arr, p) => {
    const s = [...arr].sort((a,b)=>a-b);
    if(!s.length) return 0;
    if(p<=0) return s[0];
    if(p>=100) return s[arr.length-1];
    const r = (s.length-1)*p/100;
    const rf = Math.ceil(r) - r;
    return s[Math.floor(r)]*rf + s[Math.ceil(r)]*(1-rf);
  };
  const median = (arr) => percentile(arr, 50);
  // Order Booked - Time on Page
  function isMetric(event) {
    return event.name === "Order Completed";
  }
  // Last 90 days - Metric value (Order Booked - Time on Page)
  return Events({
    "from_date": "2023-12-02",
    "to_date": "2024-03-02",
    "event_selectors": [
      {
        "event": "Order Completed"
      }
    ]
  })
  .filter(function(event) {
    if(isMetric(event)) return true;
    return false;
  })
  // Metric value per user
  .groupByUser(function(state, events) {
    state = state || {date: null, metricValue: []};
    for(var i=0; i<events.length; i++) {
      state.date = state.date || events[i].time;
      const event = events[i];
      if(isMetric(event)) {
        state.metricValue.push(event.properties["timeOnPage"]);
      }
    }
    return state;
  })
  // Remove users that did not convert
  .filter(function(ev) {
    return ev.value.date && ev.value.metricValue.length > 0;
  })
  // Aggregate metric values per user
  .map(function(user) {
    // Metric - Order Booked - Time on Page
    user.value.metricValue = !user.value.metricValue.length ? 0 : (
      (values => sum(values))(user.value.metricValue)
    );
    return user;
  })
  .reduce([
    // Overall summary metrics
    mixpanel.reducer.numeric_summary('value.metricValue'),
    // Summary metrics by date
    (prevs, events) => {
      const dates = {};
      prevs.forEach(prev => {
        prev.dates.forEach(d=>{
          dates[d.date] = dates[d.date] || {count:0, sum:0, sum_squares:0};
          dates[d.date].count += d.count;
          dates[d.date].sum += d.sum;
          dates[d.date].sum_squares += d.sum_squares;
        })
      });
      events.forEach(e=>{
        const date = (new Date(e.value.date)).toISOString().substr(0,10);
        dates[date] = dates[date] || {count:0, sum:0, sum_squares:0};
        dates[date].count++;
        dates[date].sum += e.value.metricValue;
        dates[date].sum_squares += Math.pow(e.value.metricValue, 2);
      });
      return {
        type: "byDate",
        dates: Object.keys(dates).map(d => ({
          date: d,
          ...dates[d]
        }))
      };
    }
  ])
  // Transform into easy-to-use objects
  .map(vals => vals.map(val => {
    if(val.count) return {type: "overall", ...val};
    return val;
  }));
}