From dc8c94d036ca6ee5f3fbed839770ce5a902cca11 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Iv=C3=A1n=20Ovejero?= <ivov.src@gmail.com>
Date: Fri, 2 Aug 2024 12:01:42 +0200
Subject: [PATCH] ci: Introduce lint rule `no-type-unsafe-event-emitter`
 (no-changelog) (#10254)

---
 packages/@n8n_io/eslint-config/local-rules.js | 30 +++++++++++++++++++
 packages/cli/.eslintrc.js                     |  7 +++++
 .../MessageEventBus/MessageEventBus.ts        |  2 ++
 3 files changed, 39 insertions(+)

diff --git a/packages/@n8n_io/eslint-config/local-rules.js b/packages/@n8n_io/eslint-config/local-rules.js
index c9b533a032..152415e14c 100644
--- a/packages/@n8n_io/eslint-config/local-rules.js
+++ b/packages/@n8n_io/eslint-config/local-rules.js
@@ -448,6 +448,36 @@ module.exports = {
 			};
 		},
 	},
+
+	'no-type-unsafe-event-emitter': {
+		meta: {
+			type: 'problem',
+			docs: {
+				description: 'Disallow extending from `EventEmitter`, which is not type-safe.',
+				recommended: 'error',
+			},
+			messages: {
+				noExtendsEventEmitter: 'Extend from the type-safe `TypedEmitter` class instead.',
+			},
+		},
+		create(context) {
+			return {
+				ClassDeclaration(node) {
+					if (
+						node.superClass &&
+						node.superClass.type === 'Identifier' &&
+						node.superClass.name === 'EventEmitter' &&
+						node.id.name !== 'TypedEmitter'
+					) {
+						context.report({
+							node: node.superClass,
+							messageId: 'noExtendsEventEmitter',
+						});
+					}
+				},
+			};
+		},
+	},
 };
 
 const isJsonParseCall = (node) =>
diff --git a/packages/cli/.eslintrc.js b/packages/cli/.eslintrc.js
index ac66574887..bb1041607d 100644
--- a/packages/cli/.eslintrc.js
+++ b/packages/cli/.eslintrc.js
@@ -21,6 +21,7 @@ module.exports = {
 	rules: {
 		'n8n-local-rules/no-dynamic-import-template': 'error',
 		'n8n-local-rules/misplaced-n8n-typeorm-import': 'error',
+		'n8n-local-rules/no-type-unsafe-event-emitter': 'error',
 		complexity: 'error',
 
 		// TODO: Remove this
@@ -44,6 +45,12 @@ module.exports = {
 				'n8n-local-rules/misplaced-n8n-typeorm-import': 'off',
 			},
 		},
+		{
+			files: ['./test/**/*.ts'],
+			rules: {
+				'n8n-local-rules/no-type-unsafe-event-emitter': 'off',
+			},
+		},
 		{
 			files: ['./src/decorators/**/*.ts'],
 			rules: {
diff --git a/packages/cli/src/eventbus/MessageEventBus/MessageEventBus.ts b/packages/cli/src/eventbus/MessageEventBus/MessageEventBus.ts
index 758eeb5ae5..eeb868798b 100644
--- a/packages/cli/src/eventbus/MessageEventBus/MessageEventBus.ts
+++ b/packages/cli/src/eventbus/MessageEventBus/MessageEventBus.ts
@@ -52,6 +52,8 @@ export interface MessageEventBusInitializeOptions {
 }
 
 @Service()
+// TODO: Convert to TypedEventEmitter
+// eslint-disable-next-line n8n-local-rules/no-type-unsafe-event-emitter
 export class MessageEventBus extends EventEmitter {
 	private isInitialized = false;