smarter node modules path resolving (microsoft#2558)

Co-authored-by: Djordje Dimitrijev <v-djordjed@microsoft.com>

Author: wjaykim

android/codepush.gradle

@@ -17,6 +17,41 @@ void runBefore(String dependentTaskName, Task task) {
     }
 }
 
+/**
+ * Finds the path of the installed npm package with the given name using Node's
+ * module resolution algorithm, which searches "node_modules" directories up to
+ * the file system root. This handles various cases, including:
+ *
+ *   - Working in the open-source RN repo:
+ *       Gradle: /path/to/react-native/ReactAndroid
+ *       Node module: /path/to/react-native/node_modules/[package]
+ *
+ *   - Installing RN as a dependency of an app and searching for hoisted
+ *     dependencies:
+ *       Gradle: /path/to/app/node_modules/react-native/ReactAndroid
+ *       Node module: /path/to/app/node_modules/[package]
+ *
+ *   - Working in a larger repo (e.g., Facebook) that contains RN:
+ *       Gradle: /path/to/repo/path/to/react-native/ReactAndroid
+ *       Node module: /path/to/repo/node_modules/[package]
+ *
+ * The search begins at the given base directory (a File object). The returned
+ * path is a string.
+ */
+static def findNodeModulePath(baseDir, packageName) {
+    def basePath = baseDir.toPath().normalize()
+    // Node's module resolution algorithm searches up to the root directory,
+    // after which the base path will be null
+    while (basePath) {
+        def candidatePath = Paths.get(basePath.toString(), "node_modules", packageName)
+        if (candidatePath.toFile().exists()) {
+            return candidatePath.toString()
+        }
+        basePath = basePath.getParent()
+    }
+    return null
+}
+
 android.buildTypes.each { buildType ->
     // to prevent incorrect long value restoration from strings.xml we need to wrap it with double quotes
     // https://github.com/microsoft/cordova-plugin-code-push/issues/264
@@ -34,11 +69,9 @@ gradle.projectsEvaluated {
 
         def nodeModulesPath;
         if (project.hasProperty('nodeModulesPath')) {
-            nodeModulesPath = project.nodeModulesPath
-        } else if (config.root) {
-            nodeModulesPath = Paths.get(config.root.asFile.get().absolutePath, "/node_modules");
+            nodeModulesPath = "${project.nodeModulesPath}/react-native-code-push"
         } else {
-            nodeModulesPath = "../../node_modules";
+            nodeModulesPath = findNodeModulePath(projectDir, "react-native-code-push")
         }
 
         def targetName = variant.name.capitalize()
@@ -71,7 +104,7 @@ gradle.projectsEvaluated {
             generateBundledResourcesHash = tasks.create(
                     name: "generateBundledResourcesHash${targetName}",
                     type: Exec) {
-                commandLine (*nodeExecutableAndArgs, "${nodeModulesPath}/react-native-code-push/scripts/generateBundledResourcesHash.js", resourcesDir, jsBundleFile, jsBundleDir)
+                commandLine (*nodeExecutableAndArgs, "${nodeModulesPath}/scripts/generateBundledResourcesHash.js", resourcesDir, jsBundleFile, jsBundleDir)
 
                 enabled !debuggableVariants.contains(variant.name) ?: targetName.toLowerCase().contains("release")
             }
@@ -101,14 +134,14 @@ gradle.projectsEvaluated {
             generateBundledResourcesHash = tasks.create(
                     name: "generateBundledResourcesHash${targetName}",
                     type: Exec) {
-                commandLine (*nodeExecutableAndArgs, "${nodeModulesPath}/react-native-code-push/scripts/generateBundledResourcesHash.js", resourcesDir, jsBundleFile, jsBundleDir, resourcesMapTempFileName)
+                commandLine (*nodeExecutableAndArgs, "${nodeModulesPath}/scripts/generateBundledResourcesHash.js", resourcesDir, jsBundleFile, jsBundleDir, resourcesMapTempFileName)
             }
 
             // Make this task run right before the bundle task
             def recordFilesBeforeBundleCommand = tasks.create(
                     name: "recordFilesBeforeBundleCommand${targetName}",
                     type: Exec) {
-                commandLine (*nodeExecutableAndArgs, "${nodeModulesPath}/react-native-code-push/scripts/recordFilesBeforeBundleCommand.js", resourcesDir, resourcesMapTempFileName)
+                commandLine (*nodeExecutableAndArgs, "${nodeModulesPath}/scripts/recordFilesBeforeBundleCommand.js", resourcesDir, resourcesMapTempFileName)
             }
 
             recordFilesBeforeBundleCommand.dependsOn("merge${targetName}Resources")