bufferstreams

bufferstreams

Abstract streams to deal with the whole buffered contents.

bufferstreams abstracts streams to allow you to deal with their whole content in a single buffer when it becomes necessary (by example: a legacy library that do not support streams).

It is not a good practice (dealing with the whole stream content means you need to keep the whole stream content in memory which is probably not what you intent by using streams), just some glue. Using bufferstreams means:

• there is no library dealing with streams for your needs
• you filled an issue to the wrapped library to support streams

bufferstreams can also be used to control the whole stream content in a single point of a streaming pipeline for testing purposes.

## Usage

Install the npm module:

npm install bufferstreams --save

Then, in your scripts:

import fs from 'fs';
import { BufferStream } from 'bufferstreams';

fs.createReadStream('input.txt')
  .pipe(
    new BufferStream((err, buf, cb) => {
      // err will be filled with an error if the piped in stream emits one.
      if (err) {
        throw err;
      }

      // buf will contain the whole piped in stream contents
      buf = Buffer.from(buf.toString('utf-8').replace('foo', 'bar'));

      // cb is a callback to pass the result back to the piped out stream
      // first argument is an error that will be emitted if any
      // the second argument is the modified buffer
      cb(null, buf);
    }),
  )
  .pipe(fs.createWriteStream('output.txt'));

Note that you can use bufferstreams with the objectMode option. In this case, the given buffer will be an array containing the streamed objects:

new BufferStreams(myCallback, { objectMode: true });

bufferstreams exposes a utility function for functional programming:

import { streamBuffer } from 'bufferstreams';

process.stdin.pipe(streamBuffer(myCallback)).pipe(process.stdout);

Finally bufferstreams exposes another function for objects mode buffering:

import { bufferObjects } from 'bufferstreams';

process.stdin.pipe(bufferObjects(myCallback)).pipe(process.stdout);

Contributing

Feel free to contribute with your code if you agree with publishing it under the MIT license.

API

Classes

BufferStream

Buffer the stream content and bring it into the provided callback

Functions

bufferStream(bufferCallback, options) ⇒

Utility function if you prefer a functional way of using this lib

bufferObjects(bufferCallback, options) ⇒

Utility function to buffer objet mode streams

BufferStream

Buffer the stream content and bring it into the provided callback

Kind: global class

new BufferStream(bufferCallback, options)

Param	Type	Description
bufferCallback	function	A function to handle the buffered content.
options	Object	inherits of Stream.Duplex, the options are passed to the parent constructor so you can use it's options too.
options.objectMode	boolean	Use if piped in streams are in object mode. In this case, an array of the buffered will be transmitted to the callback function.

bufferStream(bufferCallback, options) ⇒

Utility function if you prefer a functional way of using this lib

Kind: global function
Returns: Stream

Param
bufferCallback
options

bufferObjects(bufferCallback, options) ⇒

Utility function to buffer objet mode streams

Kind: global function
Returns: Stream

Param
bufferCallback
options

Authors

• Nicolas Froidure

License

MIT