node.js : EventEmitter, nextTick and setImmediate

process_emit.js

process.on('msg', function(message) {
  console.log(message);
});

console.log('--- before emit msg');
process.emit('msg', 'foo');
console.log('--- after  emit msg');

// $ node process_emit.js
// --- before called emit msg
// foo
// --- after  called emit msg
// $ 

process_emit_nextTick.js

process.on('msg', function(message) {
  console.log(message);
});

console.log('--- before called emit msg');
process.nextTick(function(){
  process.emit('msg', 'foo');
});
console.log('--- after  called emit msg');

// $ node process_emit_nextTick.js
// --- before called emit msg
// --- after  called emit msg
// foo
// $

process_emit_nextTick_large.js

/* initial */
var fs = require('fs');
var largefile = '';
if (process.platform === 'win32') {
    largefile = 'c:/Program Files/Windows Photo Viewer/ImagingEngine.dll';
} else {
    largefile = '/var/log/syslog.2.gz';
}
var reader = fs.createReadStream(largefile);
var times = 2;

/* io access */
var count_on = 0;
reader.on('data', function (chunk) {
    console.log('--- [', count_on, ']', 'on_chuck');
    count_on++;

    if (count_on > times) {
        reader.pause();
    }
});

/* nextTick loop */
process.on('msg', function (message, count) {
    console.log('[', count, ']', message);
    if (count > times) {
    } else {
        console.log('--- before called(registed) emit msg');
        process.nextTick(function () {
            process.emit('msg', 'foo', ++count);
        });
        console.log('--- after  called(registed) emit msg');
    }
});
console.log('--- before called(registed) emit msg');
process.nextTick(function () {
    process.emit('msg', 'foo', 0/* initial count */);
});
console.log('--- after  called(registed) emit msg');

// $ node process_emit_nextTick_large.js
// --- before called(registed) emit msg
// --- after  called(registed) emit msg
// [ 0 ] foo
// --- before called(registed) emit msg
// --- after  called(registed) emit msg
// [ 1 ] foo
// --- before called(registed) emit msg
// --- after  called(registed) emit msg
// [ 2 ] foo
// --- before called(registed) emit msg
// --- after  called(registed) emit msg
// [ 3 ] foo
// --- [ 0 ] on_chuck
// --- [ 1 ] on_chuck
// --- [ 2 ] on_chuck
// $

process_emit_setImmediate.js

process.on('msg', function(message) {
  console.log(message);
});

console.log('--- before called emit msg');
setImmediate(function(){
  process.emit('msg', 'foo');
});
console.log('--- after  called emit msg');

// $ node process_emit_setImmeiate.js
// --- before called emit msg
// --- after  called emit msg
// foo
// $

process_emit_setImmediate_large.js

/* initial */
var fs = require('fs');
var largefile = '';
if (process.platform === 'win32') {
    largefile = 'c:/Program Files/Windows Photo Viewer/ImagingEngine.dll';
} else {
    largefile = '/var/log/syslog.2.gz';
}
var reader = fs.createReadStream(largefile);
var times = 2;

/* io access */
var count_on = 0;
reader.on('data', function (chunk) {
    console.log('--- [', count_on, ']', 'on_chuck');
    count_on++;

    if (count_on > times) {
        reader.pause();
    }
});

/* nextTick loop */
process.on('msg', function (message, count) {
    console.log('[', count, ']', message);
    if (count > times) {
    } else {
        console.log('--- before called(registed) emit msg');
        setImmediate(function () {
            process.emit('msg', 'foo', ++count);
        });
        console.log('--- after  called(registed) emit msg');
    }
});
console.log('--- before called(registed) emit msg');
setImmediate(function () {
    process.emit('msg', 'foo', 0/* initial count */);
});
console.log('--- after  called(registed) emit msg');

// $ node process_emit_setImmediate_large.js
// --- before called(registed) emit msg
// --- after  called(registed) emit msg
// [ 0 ] foo
// --- before called(registed) emit msg
// --- after  called(registed) emit msg
// [ 1 ] foo
// --- before called(registed) emit msg
// --- after  called(registed) emit msg
// --- [ 0 ] on_chuck
// [ 2 ] foo
// --- before called(registed) emit msg
// --- after  called(registed) emit msg
// --- [ 1 ] on_chuck
// [ 3 ] foo
// --- [ 2 ] on_chuck
// $