eslint-plugin: added missing deps + lint config

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/eslint-plugin/.eslintrc.js

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2023 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Custom lint config here since source is ES5
+module.exports = {
+  plugins: ['import'],
+  parserOptions: {
+    ecmaVersion: 5,
+  },
+  rules: {
+    'import/no-extraneous-dependencies': [
+      'error',
+      {
+        devDependencies: false,
+        optionalDependencies: true,
+        peerDependencies: true,
+        bundledDependencies: true,
+      },
+    ],
+    'no-unused-expressions': 'off',
+  },
+};

packages/eslint-plugin/package.json

@@ -12,5 +12,14 @@
     "directory": "packages/eslint-plugin"
   },
   "license": "Apache-2.0",
-  "main": "./index.js"
+  "main": "./index.js",
+  "scripts": {
+    "lint": "backstage-cli package lint"
+  },
+  "dependencies": {
+    "@manypkg/get-packages": "^1.1.3"
+  },
+  "devDependencies": {
+    "@backstage/cli": "workspace:^"
+  }
 }

yarn.lock

@@ -4098,6 +4098,9 @@ __metadata:
 "@backstage/eslint-plugin@workspace:packages/eslint-plugin":
   version: 0.0.0-use.local
   resolution: "@backstage/eslint-plugin@workspace:packages/eslint-plugin"
+  dependencies:
+    "@backstage/cli": "workspace:^"
+    "@manypkg/get-packages": ^1.1.3
   languageName: unknown
   linkType: soft