try {
  // Ensure you always wrap an optional require in the try block NODE-3199
  BSON = require('bson-ext');
} catch {} // eslint-disable-line

//it should be 
try {
  // Ensure you always wrap an optional require in the try block NODE-3199
  BSON = require('bson-ext');
}catch(err){} // eslint-disable-line