✨ Add Activation Trigger (#1570)

* ✨ n8n start trigger node

* first declaration of WorkflowActivationMode

* implement first WorkflowActivationMode: 'init', 'create', 'update', 'activate'

* fix Server missing id

* add activation infos to triggers

* remove WorkflowActivationMode from webhook execution function

* add some missing activation and add manual activation

* clean up and fix some code

* fix UnhandledPromiseRejectionWarning: Error: Overwrite NodeExecuteFunctions.getExecuteTriggerFunctions.emit function!

* fix spaces

* use a better name for the node

* fix ident in package.json

* Contributions to lublak's PR #1287

* Fixed linting issues and change the way parameters are displayed

* ⚡ Fix name and minor improvements

Co-authored-by: lublak <lublak.de@gmail.com>
Co-authored-by: lublak <44057030+lublak@users.noreply.github.com>
Co-authored-by: Jan Oberhauser <jan.oberhauser@gmail.com>

packages/nodes-base/nodes/ActivationTrigger.node.ts

@@ -0,0 +1,73 @@
+import { ITriggerFunctions } from 'n8n-core';
+import {
+	INodeType,
+	INodeTypeDescription,
+	ITriggerResponse,
+} from 'n8n-workflow';
+
+export class ActivationTrigger implements INodeType {
+	description: INodeTypeDescription = {
+		displayName: 'Activation Trigger',
+		name: 'activationTrigger',
+		icon: 'fa:play-circle',
+		group: ['trigger'],
+		version: 1,
+		description: 'Executes whenever the workflow becomes active.',
+		defaults: {
+			name: 'Activation Trigger',
+			color: '#00e000',
+		},
+		inputs: [],
+		outputs: ['main'],
+		properties: [
+			{
+				displayName: 'Events',
+				name: 'events',
+				type: 'multiOptions',
+				required: true,
+				default: [],
+				description: 'Specifies under which conditions an execution should happen:<br />' +
+					'- <b>Activation</b>: Workflow gets activated<br />' +
+					'- <b>Update</b>: Workflow gets saved while active<br>' +
+					'- <b>Start</b>: n8n starts or restarts',
+				options: [
+					{
+						name: 'Activation',
+						value: 'activate',
+						description: 'Run when workflow gets activated',
+					},
+					{
+						name: 'Start',
+						value: 'init',
+						description: 'Run when n8n starts or restarts',
+					},
+					{
+						name: 'Update',
+						value: 'update',
+						description: 'Run when workflow gets saved while it is active',
+					},
+				],
+			},
+		],
+	};
+
+
+	async trigger(this: ITriggerFunctions): Promise<ITriggerResponse> {
+		const events = this.getNodeParameter('events', []) as string[];
+
+		const activationMode = this.getActivationMode();
+
+		if (events.includes(activationMode)) {
+			this.emit([this.helpers.returnJsonArray([{ activation: activationMode }])]);
+		}
+
+		const self = this;
+		async function manualTriggerFunction() {
+			self.emit([self.helpers.returnJsonArray([{ activation: 'manual' }])]);
+		}
+
+		return {
+			manualTriggerFunction,
+		};
+	}
+}