denoland/deno · error · NodeTypeError

ERR_INVALID_ARG_TYPE

ERR_INVALID_ARG_TYPE

Error message

The "options.${name}" property must be one of type string, undefined, or null

What it means

validateHost() in the http/https ClientRequest polyfill enforces that options.host and options.hostname are string, undefined, or null. Any other type (number, object, array, boolean) is rejected with ERR_INVALID_ARG_TYPE before the request is built. This mirrors Node's internal validation of the host fields in urlToHttpOptions.

Source

Thrown at ext/node/polyfills/_http_client.js:424

    timestamp: DateNow() / 1000,
    type: "Other",
    errorText,
  });
}

const kLenientAll = HTTPParser.kLenientAll | 0;
const kLenientNone = HTTPParser.kLenientNone | 0;

class HTTPClientAsyncResource {
  constructor(type, req) {
    this.type = type;
    this.req = req;
  }
}

function validateHost(host, name) {
  if (host !== null && host !== undefined && typeof host !== "string") {
    throw new ERR_INVALID_ARG_TYPE(
      `options.${name}`,
      ["string", "undefined", "null"],
      host,
    );
  }
  return host;
}

function emitErrorEvent(request, error) {
  if (onClientRequestErrorChannel.hasSubscribers) {
    onClientRequestErrorChannel.publish({
      request,
      error,
    });
  }
  // ---- Inspector: Network.loadingFailed ----------------------------------
  // Fired before the user's `error` listener so DevTools sees the failure
  // even if the listener throws.

View on GitHub (pinned to 89f33cbef2)

Solutions

1. Pass host as a string: http.request({ host: 'example.com', port: 12345 })
2. If the value is dynamic, coerce explicitly: { host: String(config.host) }
3. Pass a WHATWG URL or URL string as the first argument instead of decomposing it into an options object with typed host fields

Example fix

// before
const req = http.request({ host: 8080, path: '/' });

// after
const req = http.request({ host: '127.0.0.1', port: 8080, path: '/' });

function normalizeHost(opts) {
  for (const k of ['host', 'hostname']) {
    const v = opts[k];
    if (v !== null && v !== undefined && typeof v !== 'string') {
      opts[k] = String(v); // or throw your own config error
    }
  }
}
normalizeHost(options);

function isValidHost(v) { return v === null || v === undefined || typeof v === 'string'; }

try { http.request(options); } catch (e) { if (e.code === 'ERR_INVALID_ARG_TYPE' && /options\.(host|hostname)/.test(e.message)) { /* fix config source */ } else throw e; }

When it happens

Trigger: http.request({ host: 12345 }) (port mistakenly passed as host); passing a URL object or parsed URL JSON as host; hostname coming from untyped config or env parsing that yields a number.

Common situations: Misreading options where host should be the hostname string and port is separate; deserialized configuration where host was stored as a number; passing { host: new URL(...) } instead of the URL itself as the input argument.

Related errors

• ERR_INVALID_URL
• ERR_UNESCAPED_CHARACTERS
• ERR_INVALID_HTTP_TOKEN
• ERR_HTTP_HEADERS_SENT
• ERR_INVALID_HTTP_TOKEN

AI-assisted analysis of denoland/deno@89f33cbef2 (2026-08-16). Data as JSON: /api/errors/1d0624f5cee408ca. Report an issue: GitHub.