stream_on_data.js

var Readable = require('stream').Readable;

var readable = Readable();

var read = false;
readable._read = function () {
    console.log('reading');

    this.push(read ? null : '1');
    read = true;
};

console.log('before on()');

readable.pause();

readable.on('data', function () {
    console.log('got data in first listener');
});

readable.on('data', function () {
    console.log('got data in second listener');

    throw new Error('something unexpected happened!');
});

readable.on('end', function () {
    console.log('end of stream');
});

console.log('after on()');

readable.resume();