sindresorhus/got · error · TypeError

Invalid DNS lookup IP version: ${value as string}

Error message

Invalid DNS lookup IP version: ${value as string}

What it means

Thrown by the `dnsLookupIpVersion` setter when the value is anything other than `undefined`, `4`, or `6`. The option pins DNS resolution to an IP family and only those three values are meaningful, so any other input (a string like `'ipv4'`, a boolean, or a wrong number) is rejected.

Source

Thrown at source/core/options.ts:2948

	}

	/**
	Indicates which DNS record family to use.

	Values:
	- `undefined`: IPv4 (if present) or IPv6
	- `4`: Only IPv4
	- `6`: Only IPv6

	@default undefined
	*/
	get dnsLookupIpVersion(): DnsLookupIpVersion {
		return this.#internals.dnsLookupIpVersion;
	}

	set dnsLookupIpVersion(value: DnsLookupIpVersion) {
		if (value !== undefined && value !== 4 && value !== 6) {
			throw new TypeError(`Invalid DNS lookup IP version: ${value as string}`);
		}

		this.#internals.dnsLookupIpVersion = value;
	}

	/**
	A function used to parse JSON responses.

	@example
	```
	import got from 'got';
	import Bourne from '@hapi/bourne';

	const parsed = await got('https://example.com', {
		parseJson: text => Bourne.parse(text)
	}).json();

	console.log(parsed);

View on GitHub (pinned to e3924aa1e5)

Solutions

1. Pass one of `undefined`, `4`, or `6` (numbers, not strings).
2. If the value comes from config/env, coerce explicitly: `Number(value)` and validate before passing.
3. Map labels to numbers: `{ipv4: 4, ipv6: 6}[label]`.

Example fix

// before
await got(url, {dnsLookupIpVersion: 'ipv4'});
// after
await got(url, {dnsLookupIpVersion: 4});

function normalizeDnsVersion(value) {
  const map = {ipv4: 4, ipv6: 6, 4: 4, 6: 6, undefined};
  const v = map[value] ?? value;
  if (v !== undefined && v !== 4 && v !== 6) {
    throw new TypeError(`dnsLookupIpVersion must be undefined, 4, or 6; got ${value}`);
  }
  return v;
}

function isDnsLookupIpVersion(v: unknown): v is undefined | 4 | 6 {
  return v === undefined || v === 4 || v === 6;
}

When it happens

Trigger: Calling `got(url, {dnsLookupIpVersion: 'ipv4'})`, `{dnsLookupIpVersion: 4.0}`, `{dnsLookupIpVersion: true}`, or any value that is not exactly `undefined`, `4`, or `6`.

Common situations: Passing a string label (`'ipv4'`/`'ipv6'`) instead of the numeric family; passing a stringified number from env vars or config files.

Related errors

• The maximum acceptable retry noise is +/- 100ms, got ${value
• Unexpected option: ${key}
• Unexpected agent option: ${key}
• Unexpected timeout option: ${key}
• Using UNIX domain sockets but option `enableUnixSockets` is

AI-assisted analysis of sindresorhus/got@e3924aa1e5 (2026-08-03). Data as JSON: /data/errors/0acf834c5b2d61c3.json. Report an issue: GitHub.