refactor(core): Consolidate task result validation in Code node (#18928)

packages/nodes-base/nodes/Code/result-validation.ts

@@ -0,0 +1,174 @@
+import type { INodeExecutionData } from 'n8n-workflow';
+
+import { ReservedKeyFoundError } from './reserved-key-found-error';
+import { isObject } from './utils';
+import { ValidationError } from './ValidationError';
+
+export interface TextKeys {
+	object: {
+		singular: string;
+		plural: string;
+	};
+}
+
+export const REQUIRED_N8N_ITEM_KEYS = new Set(['json', 'binary', 'pairedItem', 'error', 'index']);
+
+export function getTextKey(
+	textKeys: TextKeys,
+	key: keyof TextKeys,
+	options?: { includeArticle?: boolean; plural?: boolean },
+) {
+	const response = textKeys[key][options?.plural ? 'plural' : 'singular'];
+	if (!options?.includeArticle) {
+		return response;
+	}
+	if (['a', 'e', 'i', 'o', 'u'].some((value) => response.startsWith(value))) {
+		return `an ${response}`;
+	}
+	return `a ${response}`;
+}
+
+export function validateItem(
+	{ json, binary }: INodeExecutionData,
+	itemIndex: number,
+	textKeys: TextKeys,
+) {
+	if (json === undefined || !isObject(json)) {
+		throw new ValidationError({
+			message: `A 'json' property isn't ${getTextKey(textKeys, 'object', { includeArticle: true })}`,
+			description: `In the returned data, every key named 'json' must point to ${getTextKey(
+				textKeys,
+				'object',
+				{ includeArticle: true },
+			)}.`,
+			itemIndex,
+		});
+	}
+
+	if (binary !== undefined && !isObject(binary)) {
+		throw new ValidationError({
+			message: `A 'binary' property isn't ${getTextKey(textKeys, 'object', { includeArticle: true })}`,
+			description: `In the returned data, every key named 'binary' must point to ${getTextKey(
+				textKeys,
+				'object',
+				{ includeArticle: true },
+			)}.`,
+			itemIndex,
+		});
+	}
+}
+
+export function validateTopLevelKeys(item: INodeExecutionData, itemIndex: number) {
+	let foundReservedKey: string | null = null;
+	const unknownKeys: string[] = [];
+
+	for (const key in item) {
+		if (!Object.prototype.hasOwnProperty.call(item, key)) continue;
+
+		if (REQUIRED_N8N_ITEM_KEYS.has(key)) {
+			foundReservedKey ??= key;
+		} else {
+			unknownKeys.push(key);
+		}
+	}
+
+	if (unknownKeys.length > 0) {
+		if (foundReservedKey) throw new ReservedKeyFoundError(foundReservedKey, itemIndex);
+
+		throw new ValidationError({
+			message: `Unknown top-level item key: ${unknownKeys[0]}`,
+			description: 'Access the properties of an item under `.json`, e.g. `item.json`',
+			itemIndex,
+		});
+	}
+}
+
+export function validateRunCodeEachItem(
+	executionResult: INodeExecutionData | undefined,
+	itemIndex: number,
+	textKeys: TextKeys,
+	normalizeItems: (items: INodeExecutionData[]) => INodeExecutionData[],
+): INodeExecutionData {
+	if (typeof executionResult !== 'object') {
+		throw new ValidationError({
+			message: `Code doesn't return ${getTextKey(textKeys, 'object', { includeArticle: true })}`,
+			description: `Please return ${getTextKey(textKeys, 'object', {
+				includeArticle: true,
+			})} representing the output item. ('${executionResult}' was returned instead.)`,
+			itemIndex,
+		});
+	}
+
+	if (Array.isArray(executionResult)) {
+		const firstSentence =
+			executionResult.length > 0
+				? `An array of ${typeof executionResult[0]}s was returned.`
+				: 'An empty array was returned.';
+		throw new ValidationError({
+			message: `Code doesn't return a single ${getTextKey(textKeys, 'object')}`,
+			description: `${firstSentence} If you need to output multiple items, please use the 'Run Once for All Items' mode instead.`,
+			itemIndex,
+		});
+	}
+
+	const [returnData] = normalizeItems([executionResult]);
+
+	validateItem(returnData, itemIndex, textKeys);
+
+	// If at least one top-level key is a supported item key (`json`, `binary`, etc.),
+	// and another top-level key is unrecognized, then the user mis-added a property
+	// directly on the item, when they intended to add it on the `json` property
+	validateTopLevelKeys(returnData, itemIndex);
+
+	return returnData;
+}
+
+export function validateRunCodeAllItems(
+	executionResult: INodeExecutionData | INodeExecutionData[] | undefined,
+	textKeys: TextKeys,
+	normalizeItems: (items: INodeExecutionData | INodeExecutionData[]) => INodeExecutionData[],
+): INodeExecutionData[] {
+	if (typeof executionResult !== 'object') {
+		throw new ValidationError({
+			message: "Code doesn't return items properly",
+			description: `Please return an array of ${getTextKey(textKeys, 'object', {
+				plural: true,
+			})}, one for each item you would like to output.`,
+		});
+	}
+
+	if (Array.isArray(executionResult)) {
+		/**
+		 * If at least one top-level key is an n8n item key (`json`, `binary`, etc.),
+		 * then require all item keys to be an n8n item key.
+		 *
+		 * If no top-level key is an n8n key, then skip this check, allowing non-n8n
+		 * item keys to be wrapped in `json` when normalizing items below.
+		 */
+		for (const item of executionResult) {
+			if (!isObject(item)) {
+				throw new ValidationError({
+					message: "Code doesn't return items properly",
+					description: `Please return an array of ${getTextKey(textKeys, 'object', {
+						plural: true,
+					})}, one for each item you would like to output.`,
+				});
+			}
+		}
+
+		const mustHaveTopLevelN8nKey = executionResult.some((item) =>
+			Object.keys(item).find((key) => REQUIRED_N8N_ITEM_KEYS.has(key)),
+		);
+
+		if (mustHaveTopLevelN8nKey) {
+			for (let index = 0; index < executionResult.length; index++) {
+				const item = executionResult[index];
+				validateTopLevelKeys(item, index);
+			}
+		}
+	}
+
+	const returnData = normalizeItems(executionResult);
+	returnData.forEach((item, index) => validateItem(item, index, textKeys));
+	return returnData;
+}