middleware-sample.js

function SampleMiddleware(options) {
  this.mwtype = 'router';
  this.features = ['params', 'query'];

  this.before = function(feature) {
    console.log(feature.params);
    console.log(feature.query);
    console.log(options.testVal);
  }
}

app.set(SampleMiddleware, { testVal: 'val' });