Remove console.logs with Webpack & Uglify

Question

I am trying to remove console.logs with Webpack\'s Uglify plugin but it seems that Uglify plugin that comes bundled with Webpack doesn\'t have that option, its

Answer 1

You can use terser-webpack-plugin compress option pure_funcs parameter to selectively drop console functions and keep the ones that you want such as console.error.

I was using "webpack": "^4.39.3" and "terser-webpack-plugin": "^2.3.2".

Steps:
1. npm install terser-webpack-plugin --save-dev
2. modify your webpack.config to set TerserPlugin as a minimizer for optimization option.

const TerserPlugin = require('terser-webpack-plugin');

module.exports = (env) => {
    return [{
        entry: '...',
        mode: 'production',
        output: {...},
        plugins: [...],
        optimization: {
            'minimize': true,
            minimizer: [new TerserPlugin({
                terserOptions: { 
                    compress: { 
                        pure_funcs: [
                            'console.log', 
                            'console.info', 
                            'console.debug', 
                            'console.warn'
                        ] 
                    } 
                 }
            })],
        },
        module: {...}
    }];
};

Answer 2

Try drop_console:

plugins: [
    new Webpack.optimize.UglifyJsPlugin({
      compress: {
        drop_console: true,
      }
    }
]

Update: For webpack v4 it has changed a little:

const UglifyJSPlugin = require('uglifyjs-webpack-plugin');

...

optimization: {
  minimizer: [
    new UglifyJSPlugin({
      uglifyOptions: {
        compress: {
          drop_console: true,
        }
      }
    })
  ]
}

I personally think console logs (especially console.error) are very useful on prod and think it's a good idea to keep them. If you really want to drop specific console functions such as just console.log you should use pure_funcs option e.g. pure_funcs: ['console.log'] and this will drop console.log since pure functions do not produce side effects then Uglify can discard ones not assigned to anything.

optimization: {
  minimizer: [
    new UglifyJSPlugin({
      uglifyOptions: {
        compress: {
          // Drop only console.logs but leave others
          pure_funcs: ['console.log'],
        },
        mangle: {
          // Note: I'm not certain this is needed.
          reserved: ['console.log']
        }
      }
    })
  ]
}

For TerserJS (Uglify is deprecated and does not support new JS features you should NOT use it)

optimization: {
  minimizer: [
    new TerserPlugin({
      terserOptions: {
        compress: {
            drop_console: true
        }
      }
    })
  ]
}

As discussed you can also use pure_funcs alternatively.