n8n/packages/nodes-base/nodes/FunctionItem/FunctionItem.node.ts

import { IExecuteFunctions } from 'n8n-core';
import {
	IBinaryKeyData,
	IDataObject,
	INodeExecutionData,
	INodeType,
	INodeTypeDescription,
	NodeOperationError,
} from 'n8n-workflow';

const { NodeVM } = require('vm2');

export class FunctionItem implements INodeType {
	description: INodeTypeDescription = {
		displayName: 'Function Item',
		name: 'functionItem',
		icon: 'fa:code',
		group: ['transform'],
		version: 1,
		description: 'Run custom function code which gets executed once per item',
		defaults: {
			name: 'FunctionItem',
			color: '#ddbb33',
		},
		inputs: ['main'],
		outputs: ['main'],
		properties: [
			{
				displayName: 'JavaScript Code',
				name: 'functionCode',
				typeOptions: {
					alwaysOpenEditWindow: true,
					codeAutocomplete: 'functionItem',
					editor: 'code',
					rows: 10,
				},
				type: 'string',
				default: `// Code here will run once per input item.
// More info and help: https://docs.n8n.io/nodes/n8n-nodes-base.functionItem

// Add a new field called 'myNewField' to the JSON of the item
item.myNewField = 1;

// You can write logs to the browser console
console.log('Done!');

return item;`,
				description: 'The JavaScript code to execute for each item.',
				noDataExpression: true,
			},
		],
	};

	async execute(this: IExecuteFunctions): Promise<INodeExecutionData[][]> {
		const items = this.getInputData();

		const returnData: INodeExecutionData[] = [];
		const length = items.length as unknown as number;
		let item: INodeExecutionData;

		for (let itemIndex = 0; itemIndex < length; itemIndex++) {
			try {
				item = items[itemIndex];

				// Copy the items as they may get changed in the functions
				item = JSON.parse(JSON.stringify(item));

				// Define the global objects for the custom function
				const sandbox = {
					getBinaryData: (): IBinaryKeyData | undefined => {
						return item.binary;
					},
					getNodeParameter: this.getNodeParameter,
					getWorkflowStaticData: this.getWorkflowStaticData,
					helpers: this.helpers,
					item: item.json,
					setBinaryData: (data: IBinaryKeyData) => {
						item.binary = data;
					},
				};

				// Make it possible to access data via $node, $parameter, ...
				const dataProxy = this.getWorkflowDataProxy(itemIndex);
				Object.assign(sandbox, dataProxy);

				const mode = this.getMode();

				const options = {
					console: (mode === 'manual') ? 'redirect' : 'inherit',
					sandbox,
					require: {
						external: false as boolean | { modules: string[] },
						builtin: [] as string[],
					},
				};

				if (process.env.NODE_FUNCTION_ALLOW_BUILTIN) {
					options.require.builtin = process.env.NODE_FUNCTION_ALLOW_BUILTIN.split(',');
				}

				if (process.env.NODE_FUNCTION_ALLOW_EXTERNAL) {
					options.require.external = { modules: process.env.NODE_FUNCTION_ALLOW_EXTERNAL.split(',') };
				}

				const vm = new NodeVM(options);

				if (mode === 'manual') {
					vm.on('console.log', this.sendMessageToUI);
				}

				// Get the code to execute
				const functionCode = this.getNodeParameter('functionCode', itemIndex) as string;

				let jsonData: IDataObject;
				try {
					// Execute the function code
					jsonData = await vm.run(`module.exports = async function() {${functionCode}\n}()`, __dirname);
				} catch (error) {
					if (this.continueOnFail()) {
						returnData.push({json:{ error: error.message }});
						continue;
					} else {
						// Try to find the line number which contains the error and attach to error message
						const stackLines = error.stack.split('\n');
						if (stackLines.length > 0) {
							const lineParts = stackLines[1].split(':');
							if (lineParts.length > 2) {
								const lineNumber = lineParts.splice(-2, 1);
								if (!isNaN(lineNumber)) {
									error.message = `${error.message} [Line ${lineNumber} | Item Index: ${itemIndex}]`;
									return Promise.reject(error);
								}
							}
						}

						error.message = `${error.message} [Item Index: ${itemIndex}]`;

						return Promise.reject(error);
					}
				}

				// Do very basic validation of the data
				if (jsonData === undefined) {
					throw new NodeOperationError(this.getNode(), 'No data got returned. Always an object has to be returned!');
				}

				const returnItem: INodeExecutionData = {
					json: jsonData,
				};

				if (item.binary) {
					returnItem.binary = item.binary;
				}

				returnData.push(returnItem);
			} catch (error) {
				if (this.continueOnFail()) {
					returnData.push({json:{ error: error.message }});
					continue;
				}
				throw error;
			}
		}
		return this.prepareOutputData(returnData);
	}
}