How to Fix Webpack: Conflicting values for ‘process.env.NODE_ENV’

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Webpack: Conflicting values for ‘process.env.NODE_ENV’ error occurs when you “configure DefinePlugin incorrectly or try to reassign process.env.NODE_ENV when instantiating the plugin.”

DefinePlugin allows you to define global constants that can be configured at compile time. It is specifically helpful for having development-only code or API endpoints based on the build environment.

Reproduce the error

const webpack = require('webpack');

module.exports = {
  plugins: [
    new webpack.DefinePlugin({
      'process.env.NODE_ENV': 'production'
    })
  ]
}

This is the wrong way!

How to fix the error?

To fix the Webpack: Conflicting values for ‘process.env.NODE_ENV’ error, use JSON.stringify() method in the context of Webpack’s DefinePlugin because of how the plugin works. The DefinePlugin performs a direct text replacement in the source code based on your keys and values.

const webpack = require('webpack');

module.exports = {
  plugins: [
    new webpack.DefinePlugin({
      'process.env.NODE_ENV': JSON.stringify('production')
    })
  ]
}

In short, the JSON.stringify() method ensures that the value you want to inject is correctly formatted as a string literal in the resulting code. This way, you won’t accidentally introduce syntax errors or unexpected behavior.

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