Gets all upcoming Stripe invoices into a csv that you can open in Excel.

main.ts

/* Stripe doesn't provide an endpoint to get all upcoming invoices,
 * instead you have to fetch them one by one for each subscriber.
 * This script gets all upcoming stripe invoices and puts them in
 * an easy to read CSV file you can open in excel.
 *
 * This tool can be useful for companies with few subscriptions to
 * see which customer's subscriptions will renew soon so they can maybe
 * get ahead of it, maybe provide some extra customer service
 * in advance or something.
 */

import Stripe from 'stripe';
import fs from 'fs-extra';
import path from 'path';
import Bottleneck from 'bottleneck';

const reqLimiter = new Bottleneck({ minTime: 40, maxConcurrent: 5 });

/*******************************************
 * Replace the below string with your stripe key.
 ******************************************/
const stripe = new Stripe('PUT YOUR STRIPE KEY HERE', { apiVersion: '2020-08-27' });

main();

export default async function main () {
  const subs = await getAllSubs();
  const upcomingInvoices = await getUpcomingInvoices({ subs });
  const csv = invoicesToCsv({ invoices: upcomingInvoices });
  exportCsvFile({ csv });
  return 0
}

function exportCsvFile({ csv }: { csv: string }): void {
  // This line assumes this file is in a src directory, and is outputting to a sibling dist directory.
  const csvPath = path.resolve(__dirname, '..', 'dist', 'upcoming-stripe-payments.csv');
  fs.outputFileSync(csvPath, csv);
  console.log(`Generated csv with ${csv.split('\n').length} lines to ${csvPath}`);
  return;
}

/**
 * A Stripe invoice with customer and subscription properties included.
 */
interface InvoiceCusSub extends Stripe.Response<Stripe.Invoice> {
  customer: Stripe.Customer
  subscription: Stripe.Subscription
}

async function getUpcomingInvoices({ subs } : { subs: Stripe.Subscription[] }): Promise<InvoiceCusSub[]> {
  return Promise.all(
    subs.map(
      (sub, i) => reqLimiter.schedule((() => {
        console.log('Invoice request: ' + (i + 1));
        return stripe.invoices.retrieveUpcoming({
          subscription: sub.id, expand: ['customer', 'subscription']
        });
      }) as () => Promise<InvoiceCusSub>)
    )
  );
}

function invoicesToCsv({ invoices } : { invoices: InvoiceCusSub[] }) {
  // Sort in ascending order of customer's next payment date (current_period_end). 
  const orderedInvoices = [ ...invoices ].sort((a, b) => a.subscription.current_period_end - b.subscription.current_period_end);
  const header = 'email,subscription,price,renewal date\n';
  const rows = orderedInvoices.reduce<string>((acc, invoice) => (
    acc + invoiceToCsvLine({ invoice })
  ), '');
  return header + rows;
}

function invoiceToCsvLine({ invoice } : { invoice: InvoiceCusSub }) {
  const subscriptionNames = invoice.subscription.items.data.reduce((acc, item) => acc + item.price.id, '');
  return `${invoice.customer.email},${subscriptionNames},$${invoice.amount_due/100},${new Date(invoice.subscription.current_period_end * 1000).toLocaleDateString()}\n`;
}

async function getAllSubs() {
  const res = await reqLimiter.schedule(() => stripe.subscriptions.list({ limit: 200 }))
  return res.data;
}