Error: Using `babel-preset-react-app` requires that you specify `NODE_ENV` or `BABEL_ENV`

Can you reproduce the problem with latest npm?

yes

Can you still reproduce it?

yes

Description

When creating a new react app with create-react-app without doing anything, only running yarn start gives the following error :

Failed to compile.
./src/index.js
Module build failed: Error: Using `babel-preset-react-app` requires that you specify `NODE_ENV` or `BABEL_ENV` environment variables. Valid values are "development", "test", and "production". Instead, received: "undefined".
 (While processing preset: "/Users/nboisvert/Git/memberzone/node_modules/babel-preset-react-app/index.js")
    at Array.map (native)

Expected behavior

Run the template React app

Actual behavior

Displays :

Environment

Run these commands in the project folder and fill in their results:

1. npm ls react-scripts (if you haven’t ejected):

memberzone@0.1.0 /Users/nboisvert/Git/memberzone
└── react-scripts@1.0.6

1. node -v: v6.2.1
2. npm -v: 4.6.1

Then, specify:

1. Operating system: macOS Sierrra 10.12.5
2. Browser and version: Google Chrome Version 58.0.3029.110 (64-bit)

Reproducible Demo

Didn’t add anything. Fresh install

[heshamelmasry77]

to fix this you need to do that : create a .babelrc file and then add this following code in it.

{
  "presets": [
    "react",
    "es2015",
    "stage-2"
  ]
}

i am using es2015 and stage-2 and for your : scripts : start.js add this :

process.env.BABEL_ENV = 'development';
process.env.NODE_ENV = 'development';

you can create a development , test, build one. my advice to you and i found that it is good to understand what is happening is to eject the react project.

[gaearon]

Please try react-scripts@1.0.7 (or create a new project). Should hopefully fix the issue.

https://github.com/facebookincubator/create-react-app/releases/tag/v1.0.7