Commission on the Tax — JavaScript Bug Hunt

Briefing

Modelled on Uber's New York City driver underpayment (acknowledged May 2017): since late 2014 Uber had been calculating its commission on NYC drivers' gross fares, including sales tax and Black Car Fund fees, instead of on the fare after those pass-through charges. Uber said it would repay the affected drivers with interest — reported at tens of millions of dollars.

statement.js is a reconstruction of the per-trip driver statement. Taxes and fees are collected from the rider and passed on; they are not part of the fare the commission applies to.

Fix statement so the commission is taken from the fare alone.

Bug report

BUG-NYC-COMM · Priority: High (driver pay) · Reported by: driver support

statement(trip) — all amounts in integer cents — returns, in this key order:

• gross: trip.fare + trip.salesTax + trip.blackCarFund (what the rider paid)
• commission: Math.round(trip.fare * rates.COMMISSION_RATE) (the fare only — never tax or fees)
• taxesAndFees: trip.salesTax + trip.blackCarFund
• driverPay: trip.fare - commission

Example: fare 2000, tax 177, BCF 50 -> { gross: 2227, commission: 500, taxesAndFees: 227, driverPay: 1500 }

Observed: commission 557 and driver pay 1443 on that trip.

Logs

[payouts] trip=nyc-88213 fare=2000 tax=177 bcf=50 commission=557
[payouts] weekly statement NYC: commission base includes tax + BCF

The code as shipped

src/pay/statement.js (editable)

var rates = require("./rates");

// Per-trip driver statement. All amounts are integer cents.
exports.statement = function (trip) {
  var gross = trip.fare + trip.salesTax + trip.blackCarFund;
  var taxesAndFees = trip.salesTax + trip.blackCarFund;
  var commission = Math.round(gross * rates.COMMISSION_RATE);
  return {
    gross: gross,
    commission: commission,
    taxesAndFees: taxesAndFees,
    driverPay: gross - taxesAndFees - commission
  };
};

Read-only context: src/pay/rates.js.