error vs Error nodejs code example

Example 1: error handling in node js

app.get('/', function (req, res, next) {
  Promise.resolve().then(function () {
    throw new Error('BROKEN')
  }).catch(next) // Errors will be passed to Express.
})

Example 2: error handling in call back function in nodejs

fs.readFile('/foo.txt', function(err, data) {
  // TODO: Error Handling Still Needed!
  console.log(data);
});