backend-common: add resolvePackagePath

packages/backend-common/src/index.ts

@@ -20,4 +20,5 @@ export * from './errors';
 export * from './logging';
 export * from './middleware';
 export * from './service';
+export * from './paths';
 export * from './hot';

packages/backend-common/src/paths.ts

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2020 Spotify AB
+ *
+ * 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.
+ */
+
+/* eslint-disable @typescript-eslint/camelcase */
+
+import { resolve as resolvePath } from 'path';
+
+/**
+ * Resolve a path relative to the root of a package directory.
+ * Additional path arguments are resolved relative to the package dir.
+ *
+ * This is particularly useful when you want to access assets shipped with
+ * your backend plugin package. When doing so, do not forget to include the assets
+ * in your published package by adding them to `files` in your `package.json`.
+ */
+export function resolvePackagePath(name: string, ...paths: string[]) {
+  const req =
+    typeof __non_webpack_require__ === 'undefined'
+      ? require
+      : __non_webpack_require__;
+
+  return resolvePath(req.resolve(`${name}/package.json`), '..', ...paths);
+}