remotion-dev/remotion · error · TypeError

Each customLayerArns entry must be a non-empty string.

Error message

Each customLayerArns entry must be a non-empty string.

What it means

validateCustomLayerArns iterates over every entry of customLayerArns and throws this TypeError when an entry is not a string or is an empty string. It is a shape check that runs before the ARN regex validation, so garbage entries (null, undefined, numbers, '') fail here rather than producing a confusing invalid-ARN message.

Source

Thrown at packages/lambda/src/shared/validate-custom-layer-arns.ts:51

		throw new TypeError('customLayerArns must contain at least one Layer ARN.');
	}

	if (runtimePreference !== 'default') {
		throw new Error(
			'customLayerArns cannot be combined with a non-default runtimePreference.',
		);
	}

	if (customLayerArns.length + (enableLambdaInsights ? 1 : 0) > 5) {
		throw new Error(
			'Lambda functions support at most 5 Layers, including the Lambda Insights Layer.',
		);
	}

	const seen = new Set<string>();
	for (const layerArn of customLayerArns) {
		if (typeof layerArn !== 'string' || layerArn.length === 0) {
			throw new TypeError(
				'Each customLayerArns entry must be a non-empty string.',
			);
		}

		const match = layerArn.match(layerVersionArnRegex);
		if (!match) {
			throw new TypeError(
				`Invalid Lambda Layer version ARN: ${layerArn}. Expected arn:<partition>:lambda:<region>:<12-digit-account-id>:layer:<layer-name>:<numeric-version>.`,
			);
		}

		if (match[1] !== partition) {
			throw new Error(
				`The custom Layer ARN ${layerArn} uses partition ${match[1]}, but region ${region} uses partition ${partition}.`,
			);
		}

		if (match[2] !== region) {

View on GitHub (pinned to 10db9de073)

Solutions

1. Inspect each entry and remove/fix non-string or empty values.
2. Filter undefined values at the source, e.g. `.filter((arn): arn is string => typeof arn === 'string' && arn.length > 0)`.
3. Set the missing environment variable that was supposed to hold the ARN.

Example fix

// before
const customLayerArns = [process.env.LAYER_ARN_1, process.env.LAYER_ARN_2]; // may contain undefined
await deployFunction({region: 'us-east-1', customLayerArns});

// after
const customLayerArns = [process.env.LAYER_ARN_1, process.env.LAYER_ARN_2]
  .filter((arn): arn is string => typeof arn === 'string' && arn.length > 0);
await deployFunction({region: 'us-east-1', customLayerArns: customLayerArns.length ? customLayerArns : null});

const sane = customLayerArns.every((a) => typeof a === 'string' && a.length > 0);
if (!sane) throw new Error('customLayerArns contains empty/non-string entries');

const isNonEmptyStringArray = (v: unknown): v is string[] =>
  Array.isArray(v) && v.every((x) => typeof x === 'string' && x.length > 0);

When it happens

Trigger: Calling deployFunction with customLayerArns containing e.g. `undefined` (sparse config object values), `null`, a number, or `''`.

Common situations: Building the layer list from environment variables or config files where one entry is missing (`process.env.MY_LAYER_ARN` undefined); trailing empty string after a bad split/trim.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• customLayerArns must contain at least one Layer ARN.
• inputRange must contain only numbers
• outputStyles must contain only objects
• Argument passed to "${api}" for param "${param}" is undefine
• setImageSequence accepts a Boolean Value

AI-assisted analysis of remotion-dev/remotion@10db9de073 (2026-08-22). Data as JSON: /api/errors/02036012bb6fd526. Report an issue: GitHub.