Providing themode configuration option tells webpack to use its built-in optimizations accordingly.

string = 'production': 'none' | 'development' | 'production'

Usage

Provide themode option in the config:

module.exports={  mode:'development',};

or pass it as aCLI argument:

webpack --mode=development

The following string values are supported:

If not set, webpack setsproduction as the default value formode.

Mode: development

// webpack.development.config.jsmodule.exports={  mode:'development',};

Mode: production

// webpack.production.config.jsmodule.exports={  mode:'production',};

Mode: none

// webpack.custom.config.jsmodule.exports={  mode:'none',};

If you want to change the behavior according to themode variable inside thewebpack.config.js, you have to export a function instead of an object:

var config={  entry:'./app.js',//...};module.exports=(env, argv)=>{if(argv.mode==='development'){    config.devtool='source-map';}if(argv.mode==='production'){//...}return config;};

Further Reading

• webpack default options (source code)

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