How to suppress warnings using webpack and post css

Question

How do I suppress warnings generated by webpack loading post css files?

Warning example:

WARNING in ./~/css-loader!./~/postcss-loader!./src/components/Navigator/Navigator.css
postcss-custom-properties: C:\StackData\bd\src\components\Navigator\Navigator.css:33:9: variable '--active' is undefined and
 used without a fallback

My webpack config:

 module: {
    loaders: [
   ...
      {test: /\.css/, loader: 'style-loader!css-loader!postcss-loader'},
   ...
    ]
  },
  postcss: function () {
    return [precss, autoprefixer];
  }

Answer 1

Can you try adding

module.exports = {
  entry: ...,
  stats: {warnings:false}
  ...
}

Answer 2

You can use the stats.warningsFilter. Try with something like this:

module.exports = {
    ...
    stats: {
        warningsFilter: [
            './~/css-loader!./~/postcss-loader!./src/components/Navigator/Navigator.css'
        ]
    }
    ...
}

You can add anything that appears in the warning, even with a regex or a function. More specific is better.