remotion-dev/remotion · error

No effects were specified for duplication

Error message

No effects were specified for duplication

What it means

duplicateEffects requires at least one effect target ({effectIndex, sequenceNodePath}) to operate on. It is the batch API behind duplicateEffect; calling it with an empty `effects` array is a caller error and throws immediately, before any parsing occurs.

Solutions

1. Guard the effects array length before calling and skip/no-op when empty
2. Ensure at least one valid {effectIndex, sequenceNodePath} entry is passed
3. If this comes from UI state, re-validate the current selection when the action fires

Example fix

// before
duplicateEffects({input, effects: []});
// after
if (effects.length > 0) { await duplicateEffects({input, effects}); }

if (!Array.isArray(effects) || effects.length === 0) return null; // no-op instead of calling
duplicateEffects({input, effects});

const hasEffects = (e: EffectTarget[]): e is [EffectTarget, ...EffectTarget[]] => e.length > 0;

try { await duplicateEffects({input, effects}); } catch (e) { if ((e as Error).message === 'No effects were specified for duplication') return null; throw e; }

When it happens

Trigger: Calling duplicateEffects({input, effects: []}); calling duplicateEffect after effects computed asynchronously produced an empty selection.

Common situations: A Studio UI selection that was already emptied (effects deleted elsewhere) before the duplicate action dispatched; filtering out invalid targets leaving an empty list.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• Cannot duplicate effect
• Cannot reorder effect: source index not-found
• "colors" must be an array with at least 2 colors, but got
• "colors" must be an array with at least 2 colors, but got
• "colors" must be an array with at least 2 colors, but got

AI-assisted analysis of remotion-dev/remotion@46a3a6bf13 (2026-09-18). Data as JSON: /api/errors/2f74a3fce0854546. Report an issue: GitHub.

Appendix: source

Thrown at packages/studio-codemods/src/effect-operations.ts:463

		};
	});

export const duplicateEffects = ({
	effects,
	input,
	prettierConfigOverride,
}: {
	effects: EffectTarget[];
	input: string;
} & EffectSourceStyleOptions): Promise<{
	output: string;
	formatted: boolean;
	effectLabels: string[];
	logLines: number[];
}> =>
	Promise.resolve().then(() => {
		if (effects.length === 0) {
			throw new Error('No effects were specified for duplication');
		}

		const ast = parseAst(input);
		const snapshots = captureEffectSourceSnapshots(ast);
		const effectsByAttribute = new Map<
			JSXAttribute,
			{
				array: ArrayExpression;
				indices: Set<number>;
				effectLabels: string[];
				logLines: number[];
			}
		>();
		for (const {effectIndex, sequenceNodePath} of effects) {
			const jsx = getJsx({action: 'duplicate', ast, sequenceNodePath});
			const attr = findEffectsAttr(jsx.attributes);
			if (!attr) {
				throw new Error('Could not find effects on the target JSX element');

View on GitHub (pinned to 46a3a6bf13)