behaviors.js

const { FooData } = require('./data'); 

const updateBar = ({ fooData, bar }) => {
  if (typeof bar !== typeof '') {
    throw new Error('bar should be a valid string'); 
  }
  return FooData({
    ...fooData,
    bar,
    foobaz: bar.indexOf('?') === -1 ? fooData.foobaz : 42,
  });
}

module.exports = {
  updateBar, 
}