Use require.resolve to resolve package path (#378)

* Use `require.resolve` to resolve package path

* resolveNodeModule -> resolveNodeModuleDir

packages/cli/src/tools/config/__mocks__/resolveNodeModuleDir.js

@@ -0,0 +1,12 @@
+/**
+ * @flow
+ */
+
+const path = require('path');
+
+export default function resolveNodeModuleDir(
+  root: string,
+  packageName: string,
+): string {
+  return path.join(root, 'node_modules', packageName);
+}

packages/cli/src/tools/config/__tests__/findDependencies-test.js

@@ -10,6 +10,8 @@ import {
   getTempDirectory,
 } from '../../../../../../jest/helpers';
 
+jest.mock('../resolveNodeModuleDir');
+
 beforeEach(() => {
   cleanup(DIR);
   jest.resetModules();

packages/cli/src/tools/config/__tests__/index-test.js

@@ -12,6 +12,8 @@ import {
 
 import {logger} from '@react-native-community/cli-tools';
 
+jest.mock('../resolveNodeModuleDir');
+
 const DIR = getTempDirectory('resolve_config_path_test');
 
 // Removes string from all key/values within an object

packages/cli/src/tools/config/index.js

@@ -19,6 +19,7 @@ import {type ConfigT} from 'types';
 
 import assign from '../assign';
 import merge from '../merge';
+import resolveNodeModuleDir from './resolveNodeModuleDir';
 /**
  * Built-in platforms
  */
@@ -34,10 +35,10 @@ function loadConfig(projectRoot: string = process.cwd()): ConfigT {
 
   const finalConfig = findDependencies(projectRoot).reduce(
     (acc: ConfigT, dependencyName) => {
-      const root = path.join(projectRoot, 'node_modules', dependencyName);
-
+      let root;
       let config;
       try {
+        root = resolveNodeModuleDir(projectRoot, dependencyName);
         config =
           readLegacyDependencyConfigFromDisk(root) ||
           readDependencyConfigFromDisk(root);

packages/cli/src/tools/config/resolveNodeModuleDir.js

@@ -0,0 +1,19 @@
+/**
+ * @flow
+ */
+import path from 'path';
+
+/**
+ * Finds a path inside `node_modules`
+ */
+export default function resolveNodeModuleDir(
+  root: string,
+  packageName: string,
+): string {
+  return path.dirname(
+    // $FlowIssue: Wrong `require.resolve` type definition
+    require.resolve(path.join(packageName, 'package.json'), {
+      paths: [root],
+    }),
+  );
+}

packages/cli/src/tools/config/resolveReactNativePath.js

@@ -1,21 +1,17 @@
 /**
  * @flow
  */
-import path from 'path';
 import {CLIError} from '@react-native-community/cli-tools';
 
+import resolveNodeModuleDir from './resolveNodeModuleDir';
+
 /**
  * Finds path to React Native inside `node_modules` or throws
  * an error otherwise.
  */
 export default function resolveReactNativePath(root: string) {
   try {
-    return path.dirname(
-      // $FlowIssue: Wrong `require.resolve` type definition
-      require.resolve('react-native/package.json', {
-        paths: [root],
-      }),
-    );
+    return resolveNodeModuleDir(root, 'react-native');
   } catch (_ignored) {
     throw new CLIError(`
       Unable to find React Native files. Make sure "react-native" module is installed