Stripe revenue dashboard for Next.js

lib/revenue.ts

import Stripe from "stripe";
import type { DashboardData, RangeData } from "@/components/AnalyticsDashboard";

const stripe = new Stripe(process.env.STRIPE_SECRET_KEY!);
const DAY = 86_400; // seconds
const MONTHLY_GOAL = 20_000; // in your currency's main unit

/** Paid charges created in [from, to), unix seconds. The loop walks every page. */
async function paidCharges(from: number, to: number) {
  const charges: Stripe.Charge[] = [];
  for await (const charge of stripe.charges.list({ created: { gte: from, lt: to }, limit: 100 })) {
    if (charge.paid && !charge.refunded) charges.push(charge);
  }
  return charges;
}

const net = (c: Stripe.Charge) => (c.amount - c.amount_refunded) / 100;
const change = (now: number, before: number) => (before ? Math.round(((now - before) / before) * 1000) / 10 : 0);
const label = (secondsAgo: number, opts: Intl.DateTimeFormatOptions) =>
  new Date(Date.now() - secondsAgo * 1000).toLocaleDateString("en-US", opts);

/** 7 bars of `barDays` days each, compared with the 7 bars before them. */
async function range(barDays: number, labels: string[]): Promise<RangeData> {
  const now = Math.floor(Date.now() / 1000);
  const span = 7 * barDays * DAY;
  const [current, previous] = await Promise.all([paidCharges(now - span, now), paidCharges(now - 2 * span, now - span)]);

  const sums = Array<number>(7).fill(0);
  for (const c of current) {
    const bar = Math.min(6, Math.floor((c.created - (now - span)) / (barDays * DAY)));
    sums[bar] += net(c);
  }
  const top = Math.max(...sums, 1);
  const revenue = current.reduce((t, c) => t + net(c), 0);
  const before = previous.reduce((t, c) => t + net(c), 0);

  return {
    revenue,
    orders: current.length,
    conv: 0, // Stripe has no visitor count. Pass the rate from your analytics here.
    d: [change(revenue, before), change(current.length, previous.length), 0],
    goal: 0, // set below from the last 28 days
    bars: sums.map((v) => Math.round((v / top) * 100)),
    labels,
  };
}

export async function getRevenueData(): Promise<DashboardData> {
  const days = Array.from({ length: 7 }, (_, i) => label((6 - i) * DAY, { weekday: "short" }));
  const fourDayBars = Array.from({ length: 7 }, (_, i) => label((27 - i * 4) * DAY, { month: "short", day: "numeric" }));
  const [week, month] = await Promise.all([range(1, days), range(4, fourDayBars)]);
  const goal = Math.min(100, Math.round((month.revenue / MONTHLY_GOAL) * 100));
  return { week: { ...week, goal }, month: { ...month, goal } };
}