n8n-io/n8n · error · Error

nodeJson() requires a node or node name.

Error message

nodeJson() requires a node or node name.

What it means

nodeJson() resolves the node reference to a name via resolveNodeName() (the string itself, or node.name for a node instance). If that resolved name is falsy (empty string or undefined), this error fires because the generated $('...') reference would be invalid.

Source

Thrown at packages/@n8n/workflow-sdk/src/expression/index.ts:121

/**
 * Build an expression that references JSON data from a specific node by name.
 *
 * Prefer this over `$json` when a value comes from an AI subnode, a fan-in
 * branch, or any node other than the immediate main-flow predecessor.
 *
 * @example
 * ```typescript
 * nodeJson(telegramTrigger, 'message.chat.id')
 * // "={{ $('Telegram Trigger').item.json.message.chat.id }}"
 *
 * nodeJson('Set User', ['profile', 'user-id'])
 * // "={{ $('Set User').item.json.profile[\"user-id\"] }}"
 * ```
 */
export function nodeJson(node: NodeJsonReference, path: string | readonly string[]): string {
	const nodeName = resolveNodeName(node);
	if (!nodeName) {
		throw new Error('nodeJson() requires a node or node name.');
	}

	const pathExpression = normalizePath(path).map(formatPathSegment).join('');
	return `={{ $('${escapeNodeName(nodeName)}').item.json${pathExpression} }}`;
}

// =============================================================================
// $fromAI Expression Generator
// =============================================================================

/**
 * Sanitize a key for use in $fromAI expression.
 * Keys must be 1-64 characters, alphanumeric with underscores and hyphens only.
 *
 * @param key - The original key string
 * @returns Sanitized key that meets $fromAI requirements
 */
function sanitizeFromAIKey(key: string): string {

View on GitHub (pinned to 5ac6606e81)

Solutions

1. Pass a non-empty node name string, e.g. nodeJson('Set User', 'id').
2. If passing a node instance, ensure it was created with a non-empty name.
3. Validate the node name is truthy before calling nodeJson().

Example fix

// before
const ref = nodeJson('', 'id');
// after
const ref = nodeJson('Set User', 'id');

// Ensure the node resolves to a non-empty name before calling nodeJson().
const name = typeof node === 'string' ? node : node?.name;
if (!name) throw new Error('nodeJson needs a non-empty node name');
const ref = nodeJson(node, path);

function hasNodeName(n: unknown): n is { name: string } | string {
  return typeof n === 'string' ? n.length > 0 : !!n && typeof (n as any).name === 'string' && (n as any).name.length > 0;
}

When it happens

Trigger: nodeJson('', 'id'), nodeJson({ name: '' }, 'id'), nodeJson(undefined as any, 'id'), or passing a node instance whose name property is empty.

Common situations: Node name sourced from dynamic/empty data; referencing a node by an unset variable; LLM uses a placeholder node name.

Related errors

• nodeJson() requires a non-empty JSON path.
• expr(newCredential('${value.name}')) is invalid. Use newCred
• expr() requires a string argument, but received ${typeof val
• topK must be an integer >= 1, got ${k}
• intersection(): expected array arg, e.g. .intersection([1, 2

AI-assisted analysis of n8n-io/n8n@5ac6606e81 (2026-08-12). Data as JSON: /api/errors/c21f3d52b9d62374. Report an issue: GitHub.