scriptc/tests/fixtures/fetch/node_modules/fetchcause/index.js

// Probes the network-failure rejection's CAUSE from package code — the
// exact consumer shape: provider-utils' handleFetchError classifies
// retryable network errors by error.cause.message/.code.
export async function probeRefused(url) {
  try {
    await fetch(url);
    console.log("unexpectedly connected");
  } catch (e) {
    console.log(`err ${e.name}: ${e.message}`);
    const c = e.cause;
    if (c instanceof Error) {
      console.log(`cause ${c.message} code=${c.code} syscall=${c.syscall}`);
    } else {
      console.log(`cause missing: ${String(c)}`);
    }
  }
}