Why is the last error unhandled?

stream-errors.js

var s = require('stream');

var mys;

/* ========================================================
   Error callback first, throw
   ======================================================== */
mys = Object.create(s.Readable.prototype);
mys._read = function(size) {
  this.emit('error', new Error('test'));
}
s.Readable.call(mys, {
  objectMode: true
});

mys.on('error', function(err) {
  console.log('error on', err);
});
mys.on('data', function(x) {
  console.log('data received', x);
});
mys.on('end', function() {
  console.log('end received', x);
});


/* ========================================================
   Error callback first, data
   ======================================================== */
console.log('===========================');
mys = Object.create(s.Readable.prototype);
mys._read = function(size) {
  this.push('hello');
  this.push(null);
}
s.Readable.call(mys, {
  objectMode: true
});

mys.on('error', function(err) {
  console.log('error on', err);
});
mys.on('data', function(x) {
  console.log('data received', x);
});
mys.on('end', function() {
  console.log('end received');
});

/* ========================================================
   Error callback last, data
   ======================================================== */
console.log('===========================');
mys = Object.create(s.Readable.prototype);
mys._read = function(size) {
  this.push('hello');
  this.push(null);
}
s.Readable.call(mys, {
  objectMode: true
});

mys.on('data', function(x) {
  console.log('data received', x);
});
mys.on('end', function() {
  console.log('end received');
});
mys.on('error', function(err) {
  console.log('error on', err);
});

/* ========================================================
   Error callback last, throw
   ======================================================== */
console.log('===========================');
mys = Object.create(s.Readable.prototype);
mys._read = function(size) {
  this.emit('error', new Error('test'));
}
s.Readable.call(mys, {
  objectMode: true
});

mys.on('data', function(x) {
  console.log('data received', x);
});
mys.on('end', function() {
  console.log('end received', x);
});
mys.on('error', function(err) {
  console.log('error on', err);
});

To add, as you probably have already noticed it's not just that it's bound last, but rather that it is bound after data. Removing the data event binding for the final attempt allows this to function without error. It doesn't actually catch the error though... Curious to find out what this is about, good luck! https://gist.github.com/MattSurabian/d88a8fd249dd3702b6c4