diff --git a/packages/babel-preset-react-app/index.js b/packages/babel-preset-react-app/index.js
index fbd421beb1e..8270e5b202e 100644
--- a/packages/babel-preset-react-app/index.js
+++ b/packages/babel-preset-react-app/index.js
@@ -13,6 +13,10 @@ var path = require('path');
 const plugins = [
   // class { handleClick = () => { } }
   require.resolve('babel-plugin-transform-class-properties'),
+  // idx: The existential function.
+  // (props, _ => _.user.friends[0].friends)
+  // See https://facebook.github.io/react-native/blog/2017/03/13/idx-the-existential-function.html
+  require.resolve('babel-plugin-idx'),
   // The following two plugins use Object.assign directly, instead of Babel's
   // extends helper. Note that this assumes `Object.assign` is available.
   // { ...todo, completed: true }
diff --git a/packages/babel-preset-react-app/package.json b/packages/babel-preset-react-app/package.json
index aa955e43762..f8c0c7fa13a 100644
--- a/packages/babel-preset-react-app/package.json
+++ b/packages/babel-preset-react-app/package.json
@@ -12,6 +12,7 @@
   ],
   "dependencies": {
     "babel-plugin-dynamic-import-node": "1.0.0",
+    "babel-plugin-idx": "1.1.0",
     "babel-plugin-syntax-dynamic-import": "6.18.0",
     "babel-plugin-transform-class-properties": "6.23.0",
     "babel-plugin-transform-object-rest-spread": "6.23.0",
diff --git a/packages/react-scripts/package.json b/packages/react-scripts/package.json
index b2cb03bb972..4fd1f9f6c9c 100644
--- a/packages/react-scripts/package.json
+++ b/packages/react-scripts/package.json
@@ -47,6 +47,7 @@
     "fs-extra": "0.30.0",
     "html-webpack-plugin": "2.28.0",
     "http-proxy-middleware": "0.17.3",
+    "idx": "1.1.0",
     "jest": "18.1.0",
     "object-assign": "4.1.1",
     "postcss-loader": "1.3.3",