Function portIsFree

lib/internal/debugger/inspect_helpers.js:30–58

(host, port, timeout = 3000)

const debugRegex = /Debugger listening on ws:\/\/\[?(.+?)\]?:(\d+)\//;

async function portIsFree(host, port, timeout = 3000) {
  if (port === 0) return; // Binding to a random port.

  const retryDelay = 150;
  const ac = new AbortController();
  const { signal } = ac;

  pSetTimeout(timeout).then(() => ac.abort());

  const asyncIterator = pSetInterval(retryDelay);
  while (true) {
    await asyncIterator.next();
    if (signal.aborted) {
      throw new ERR_DEBUGGER_STARTUP_ERROR(
        `Timeout (${timeout}) waiting for ${host}:${port} to be free`);
    }
    const error = await new Promise((resolve) => {
      const socket = net.connect(port, host);
      socket.on('error', resolve);
      socket.on('connect', () => {
        socket.end();
        resolve();
      });
    });
    if (error?.code === 'ECONNREFUSED') {
      return;
    }
  }
}

function ensureTrailingNewline(text) {
  return StringPrototypeEndsWith(text, '\n') ? text : `${text}\n`;