Run react-native cli with wrapper

RN 0.42 no more accept 'root' option.
RN 0.42 requires absolute paths for 'projectRoots' option.

Author: vovkasm

package.json

@@ -5,7 +5,7 @@
   "main": "lib/index.js",
   "scripts": {
     "start": "npm run start-sample --",
-    "start-sample": "react-native start --root samples/SampleApp",
+    "start-sample": "node rn-wrapper.js start --projectRoots samples/SampleApp,.",
     "run-sample-android": "react-native run-android --root samples/SampleApp",
     "run-sample-ios": "react-native run-ios --project-path samples/SampleApp/ios"
   },

rn-wrapper.js

@@ -0,0 +1,16 @@
+
+const path = require('path')
+
+// modify paths to be absolute
+const PATH_ARG_RE = /^--?(root|projectRoots)$/
+const argv = process.argv
+for (let i = 2; i < argv.length; ++i) {
+  if (PATH_ARG_RE.test(argv[i - 1])) {
+    argv[i] = argv[i].split(',').map(function (p) {
+      return path.resolve(__dirname, p)
+    }).join(',')
+  }
+}
+
+const cli = require('react-native/cli')
+cli.run()