n8n-io/n8n · error · Error

.onTrue() is only available on IF nodes (${NODE_TYPES.IF})

Error message

.onTrue() is only available on IF nodes (${NODE_TYPES.IF})

What it means

Thrown by NodeInstanceImpl.onTrue() when isIfNodeType(this.type) returns false. The .onTrue()/.onFalse() branch builders target the true/false output ports that only exist on n8n-nodes-base.if nodes; calling onTrue on any other node type is rejected because those ports do not exist.

Source

Thrown at packages/@n8n/workflow-sdk/src/workflow-builder/node-builders/node-builder.ts:315

	 */
	output(index: number): OutputSelector<TType, TVersion, TOutput> {
		return new OutputSelectorImpl(this, index) as unknown as OutputSelector<
			TType,
			TVersion,
			TOutput
		>;
	}

	/**
	 * Start building an IF branch with the true branch target.
	 * Only available on IF nodes (n8n-nodes-base.if).
	 *
	 * @example
	 * ifNode.onTrue(trueHandler).onFalse(falseHandler)
	 */
	onTrue(target: IfElseTarget): IfElseBuilder<TOutput> {
		if (!isIfNodeType(this.type)) {
			throw new Error(`.onTrue() is only available on IF nodes (${NODE_TYPES.IF})`);
		}
		const builder = new IfElseBuilderImpl<TOutput>(
			this as unknown as NodeInstance<'n8n-nodes-base.if', string, TOutput>,
		);
		return builder.onTrue(target);
	}

	/**
	 * Start building an IF branch with the false branch target.
	 * Only available on IF nodes (n8n-nodes-base.if).
	 *
	 * @example
	 * ifNode.onFalse(falseHandler).onTrue(trueHandler)
	 */
	onFalse(target: IfElseTarget): IfElseBuilder<TOutput> {
		if (!isIfNodeType(this.type)) {
			throw new Error(`.onFalse() is only available on IF nodes (${NODE_TYPES.IF})`);
		}

View on GitHub (pinned to 5ac6606e81)

Solutions

1. Create the node with type 'n8n-nodes-base.if' before calling .onTrue().
2. For Switch nodes use .onCase(index, target); for plain fan-out use .to().
3. Type-narrow with isIfNodeType before calling .onTrue()/.onFalse().

Example fix

// before
const n = node('n8n-nodes-base.switch', 'v1', { ... });
n.onTrue(handler); // throws
// after
const ifNode = node('n8n-nodes-base.if', 'v1', { ... });
ifNode.onTrue(handler).onFalse(otherHandler);

function assertIfNode(node: NodeInstance): asserts node is NodeInstance<'n8n-nodes-base.if', string, unknown> {
  if (node.type !== 'n8n-nodes-base.if') {
    throw new Error(`.onTrue() requires an IF node, got ${node.type}`);
  }
}

assertIfNode(myNode);
myNode.onTrue(handler);

import { isIfNodeType } from '@n8n/workflow-sdk';

function isIfNode(node: NodeInstance): node is NodeInstance<'n8n-nodes-base.if', string, unknown> {
  return isIfNodeType(node.type);
}

When it happens

Trigger: Calling someNode.onTrue(handler) where someNode is a Switch, Code, HTTP, Merge, or any non-IF node type. Passing a generic NodeInstance to a helper that unconditionally calls .onTrue().

Common situations: Wrong node type selected (e.g. used Switch instead of IF); copy-paste from an IF example onto another node; dynamic node construction where the type string is wrong.

Related errors

• .onFalse() is only available on IF nodes (${NODE_TYPES.IF})
• .onCase() is only available on Switch nodes (${NODE_TYPES.SW
• SDK_REPEATED_BRANCH_WIRING
• SplitInBatches node input connections are managed by SplitIn
• SplitInBatches node output connections are managed by SplitI

AI-assisted analysis of n8n-io/n8n@5ac6606e81 (2026-08-12). Data as JSON: /api/errors/974480301583162d. Report an issue: GitHub.