@imikailoby/sats/dist/providers/base.js

Tiny non-custodial Bitcoin SDK (TS) — keys, addresses, PSBT, provider chain

import { withTimeout } from "../utils/http";
import { ProviderError, TimeoutError } from "../core/errors";
/**
 * Create a provider that tries the given providers in order with simple backoff and timeout.
 * Backoff schedule: 0ms, 250ms, 500ms.
 */
export function createProviderChain(...providersOrOptions) {
    // Options can be passed as the last argument
    let timeoutMs = 4000;
    let backoffMs = [0, 250, 500];
    const providers = [];
    providersOrOptions.forEach((item, idx) => {
        if (typeof item.getAddressUtxos === "function") {
            providers.push(item);
        }
        else if (idx === providersOrOptions.length - 1) {
            const opts = item;
            if (typeof opts.timeoutMs === "number")
                timeoutMs = opts.timeoutMs;
            if (Array.isArray(opts.backoffMs) && opts.backoffMs.length > 0)
                backoffMs = opts.backoffMs;
        }
    });
    async function tryAll(fn) {
        let lastErr;
        for (let i = 0; i < providers.length; i++) {
            const provider = providers[i];
            const delay = backoffMs[Math.min(i, backoffMs.length - 1)] ?? 0;
            if (delay > 0)
                await new Promise((r) => {
                    const t = setTimeout(r, delay);
                    t?.unref?.();
                });
            try {
                return await withTimeout(fn(provider), timeoutMs);
            }
            catch (e) {
                lastErr = e instanceof TimeoutError ? e : new ProviderError(`provider[${i}] failed`, e);
            }
        }
        throw lastErr ?? new ProviderError("no providers available");
    }
    return {
        getAddressUtxos(addr) {
            return tryAll((p) => p.getAddressUtxos(addr));
        },
        getAddressBalance(addr) {
            return tryAll((p) => p.getAddressBalance(addr));
        },
        broadcast(rawHex) {
            return tryAll((p) => (p.broadcast ? p.broadcast(rawHex) : Promise.reject(new ProviderError("broadcast not supported"))));
        },
    };
}