看起来您正在使用React开发版本的缩小版本

Question

I am using this software:

• Webpack 1.15.0
• React 15.5.4

All the stuff configured (most of) as in https://github.com/davezuko/react-redux-starter-kit

I've already developed multiple projects with the same starter kit, and never had this problem.

I launch compilation with the following command:

$ NODE_ENV=production npm run compile

ENV var is set correctly, I can see as compiler output:

app:config:project Creating default configuration. +0ms
app:config:project Looking for environment overrides for NODE_ENV    "production". +4ms
app:config:project Found overrides, applying to default configuration. +2ms
app:config:webpack Creating configuration. +0ms
app:config:webpack DefinePlugin { 'process.env': { NODE_ENV: '"production"' },
'$LOCALES': '{"en-US":"en","it-IT":"ita"}',
NODE_ENV: 'production',
__DEV__: false,
__PROD__: true,
__STAGING__: false,
__TEST__: false,
__COVERAGE__: false,
__BASENAME__: '""' } +1ms
app:config:webpack Enabling plugins for production (OccurenceOrder, Dedupe & UglifyJS). +14ms
app:config:webpack Applying ExtractTextPlugin to CSS loaders. +111ms
app:bin:compile Starting compiler. +1ms

I know that I've to inject process.env.NODE_ENV inside compiled code, because in a browser env is not usable.

I know this is done in webpack with the following (extract from my webpack.config)

webpackConfig.plugins = [
  new webpack.DefinePlugin(project.globals),
  ...
]

where projects.globals is the same as appear in the compiler output above:

config.globals = {
  'process.env'  : {
    'NODE_ENV' : JSON.stringify(config.env)
  },
  '$LOCALES'     : JSON.stringify(config.i18n.locales),
  'NODE_ENV'     : config.env,
  '__DEV__'      : config.env === 'development',
  '__PROD__'     : config.env === 'production',
  '__STAGING__'  : config.env === 'staging',
  '__TEST__'     : config.env === 'test',
  '__COVERAGE__' : !argv.watch && config.env === 'test',
  '__BASENAME__' : JSON.stringify(process.env.BASENAME || '')
}

and config.env is defined also:

const config = {
    env : process.env.NODE_ENV || 'development',
    ...

Without running the UglifyJsPlugin I can see in the output many

if (false):
   // some check like "production" !== process.env.NODE_ENV

and it seems correct, because I read in some github issue ( https://github.com/webpack/webpack/issues/868 ) that the if (false) is generated by webpack because it injects correctly the process.env.NODE_ENV value, since the original code should look something like

if (!"production" === process.env.NODE_ENV) {
   ...
   if("production" === process.env.NODE_ENV)
}

Ok, now I enable the UglifyJsPlugin:

} else if (__PROD__ || __STAGING__) {
  debug('Enabling plugins for production (OccurenceOrder, Dedupe & UglifyJS).')
  webpackConfig.plugins.push(
    new webpack.optimize.OccurrenceOrderPlugin(),
    new webpack.optimize.DedupePlugin(),
    new webpack.optimize.UglifyJsPlugin({
      compress : {
        unused    : true,
        dead_code : true,
        warnings  : false
      }
    }),
    new webpack.optimize.AggressiveMergingPlugin()
  )
}

And the output is full of

"production"!==t.env.NODE_ENV

and the warning appears in the console:

Warning: It looks like you're using a minified copy of the development build of React. When deploying React apps to production, make sure to use the production build which skips development warnings and is faster. See https://fb[dot]me/react-minification for more details.

I've tried all the methods suggested in the first 2/3 google results pages searching for such error and "webpack process.env.NODE_ENV" but with no luck.

Answer 1

(Posted solution on behalf of the question author) .

The problem was with a third party library which itself included a not minified version of React.