Open Node Streams on demand.
npm install lazystream> Create streams lazily when they are read from or written to.
> lazystream: 1.0.1
Sometimes you feel the itch to open all the files at once. You want to pass a bunch of streams around, so the consumer does not need to worry where the data comes from.
From a software design point-of-view this sounds entirely reasonable. Then there is that neat little function fs.createReadStream() that opens a file and gives you a nice fs.ReadStream to pass around, so you use what the mighty creator deities of node bestowed upon you.
> Error: EMFILE, too many open files
> ─ node
This package provides two classes based on the node's Streams3 API (courtesy of readable-stream to ensure a stable version).
A wrapper for readable streams. Extends stream.PassThrough.
fn {Function}*
The function that the lazy stream will call to obtain the stream to actually read from.
options {Object}*
Options for the underlying PassThrough stream, accessible by fn.
Creates a new readable stream. Once the stream is accessed (for example when you call its read() method, or attach a data-event listener) the fn function is called with the outer lazystream.Readable instance bound to this.
If you pass an options object to the constuctor, you can access it in your fn function.
``javascript`
new lazystream.Readable(function (options) {
return fs.createReadStream('/dev/urandom');
});
A wrapper for writable streams. Extends stream.PassThrough.
fn {Function}*
The function that the lazy stream will call to obtain the stream to actually write to.
options {Object}*
Options for the underlying PassThrough stream, accessible by fn.
Creates a new writable stream. Just like the one above but for writable streams.
`javascript`
new lazystream.Writable(function () {
return fs.createWriteStream('/dev/null');
});
`console`
$ npm install lazystream --save
lazystream@1.0.1 node_modules/lazystream
└── readable-stream@2.0.5
- #3: (finally) fixed a long-standing publishing error
- #2: unconditionally use readable-stream` _2.x_.
- #1: error events are now propagated
- _(this was the first release)_
Fork it, branch it, send me a pull request. We'll work out the rest together.
Chris Talkington and his node-archiver for providing a use-case.
Copyright (c) 2013 J. Pommerening, contributors.
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