chopper

Chopper

Chops a stream into pieces using a delimiter.

Install

$ npm install chopper

StreamChopper

The object created from StreamChopper() lets you read a line at a time from a stream in a throttled manner:

require("chopper");

stream = process.stdin
var chopper = new StreamChopper(stream, "\n", function(line) {
	chopper.pause();
	console.log(line);
	setTimeout(function() {
		chopper.resume();
	}, 500);
});

This outputs a line at a time with a 1/2 second delay between each.

All three arguments to the constructor are required.

Chopper

The object created from Chopper() cuts the stream into delimited pieces, but does not throttle itself at all. The stream for Chopper() is just sequentials calls to feed it more data via next().

Chopper() can be used 3 different ways.

Returning an Array

This:

log = console.log
var chopper = new Chopper("\0");
log(chopper.next('{"seq":0}\0'));
log(chopper.next('{"seq":1}\0'));
log(chopper.next('{"seq":'));
log(chopper.next('2}\0'));
log(chopper.next('{"seq":3}\0{"seq":4}\0'));
log(chopper.next('{"seq":5}\0{'));
log(chopper.next('"seq":6}\0'));
log(chopper.next('\0'));
log(chopper.next('{"seq":7}\0{"seq":8}\0{"seq":9}'));
log(chopper.next('\0{"seq":10}'));

Outputs:

[ '{"seq":0}' ]
[ '{"seq":1}' ]
[]
[ '{"seq":2}' ]
[ '{"seq":3}', '{"seq":4}' ]
[ '{"seq":5}' ]
[ '{"seq":6}' ]
[ '' ]
[ '{"seq":7}', '{"seq":8}' ]
[ '{"seq":9}' ]

Using a Callback

This:

var chopper = new Chopper("\n");
var f = function(m) { log(m) }
chopper.next('{"seq":0}\n', f)
chopper.next('{"seq":1}\n', f)
chopper.next('{"seq":', f)
chopper.next('2}\n', f)
chopper.next('{"seq":3}\n{"seq":4}\n', f)
chopper.next('{"seq":5}\n{', f)
chopper.next('"seq":6}\n', f)
chopper.next('\n', f)
chopper.next('{"seq":7}\n{"seq":8}\n{"seq":9}', f)
chopper.next('\n{"seq":10}', f)

Outputs this:

{"seq":0}
{"seq":1}
{"seq":2}
{"seq":3}
{"seq":4}
{"seq":5}
{"seq":6}

{"seq":7}
{"seq":8}
{"seq":9}

Using a Persistent Callback

This:

var f = function(m) { log(m) }
var chopper = new Chopper("\n", f);
chopper.next('Hello.\nGoodbye.\n')
chopper.next('Why')
chopper.next(' are you')
chopper.next(' here?\nI do not know.')
chopper.next('\nok')

Outputs this:

Hello.
Goodbye.
Why are you here?
I do not know.

The "ok" string at the end isn't recognized as it isn't terminated with \n.

Thanks

If you find errors please send me pull requests with repairs.