Property data over plain REST

// The client follows the cursor and stops when the API says to.
// Writing this loop by hand is where people stop on a short page,
// and a full page can still be the last one.
for await (const property of skautik.properties.listAll({ city: "Berlin" })) {
    await upsert(property);
}

import { ResponseError } from "@skautik/sdk";

async function withRetry<T>(call: () => Promise<T>, attempts = 5): Promise<T> {
    for (let attempt = 0; ; attempt++) {
        try {
            return await call();
        } catch (error) {
            if (!(error instanceof ResponseError)) throw error;

            const status = error.response.status;
            if (status !== 429 && status < 500) throw error;
            if (attempt === attempts - 1) throw error;

            // A 429 says exactly how long to wait. Trust it over a guess, and
            // add jitter so a fleet of workers does not all wake together.
            const after = Number(error.response.headers.get("Retry-After") ?? 0);
            const backoff = after > 0 ? after * 1000 : 2 ** attempt * 250;
            await new Promise((r) => setTimeout(r, backoff + Math.random() * 250));
        }
    }
}