piperline

Split your async code into small tasks.

Simple task pipeline runner which allows you to split you async code into small tasks.

Installation

npm

$ npm install --save piperline

Features

• async tasks
• re-usage
• interruption
• extensibility
• event-based control

Usage

Basic

var Piperline = require('piperline');

Piperline.create()
    .pipe(function(data, next, done) {
        next('foo');
    })
    .pipe(function(data, next, done) {
        next(data + ' bar');
    })
    .on('error', function(err) {
        console.error(err);
    })
    .on('done', function(result) {
        console.log(result); // foo bar
    })
    .run();

Passing initial data

var Piperline = require('piperline');

Piperline.create()
    .pipe(function(data, next, done) {
        next(data + 1);
    })
    .pipe(function(data, next, done) {
        next(data + 2);
    })
    .on('error', function(err) {
        console.error(err);
    })
    .on('done', function(result) {
        console.log(result); // 4
    })
    .run(1);

Passing callback

var pipeline = require('piperline').create();

pipeline
    .pipe(function(data, next, done) {
        next(data + 1);
    })
    .pipe(function(data, next, done) {
        next(data + 2);
    })
    .on('error', function(err) {
        console.error(err);
    })
    .on('done', function(result) {
        console.log(result); // 3
    })
    .run(0, function(err, data) {
        if (err) {
            // do stuff
        }
    });

Pipeline interruption

var Piperline = require('piperline');

Piperline.create()
    .pipe(function(data, next, done) {
        next(data + 1);
    })
    .pipe(function(data, next, done) {
        if (data === 1) {
            done(data);
        }

        next(data + 2);
    })
    .pipe(function(data, next, done) {
        next(data + 3);
    })
    .on('error', function(err) {
        console.error(err);
    })
    .on('done', function(result) {
        console.log(result); // 1
    })
    .run(0);

Re-usage

var pipeline = require('piperline').create();

pipeline
    .pipe(function(data, next, done) {
        // do stuff
        next();
    })
    .pipe(function(data, next, done) {
        // do stuff
        next();
    })
    .on('finish', () => {
        // everything is completed
    });

[1, 2, 3, 4].forEach(data => pipeline.run(data));

Manual error emitting

Emitting error via callback (done or next) by passing Error object.

var pipeline = require('piperline').create();

pipeline
    .pipe(function(data, next) {
        next(data);
    })
    .pipe(function(data, next, done) {
        done(new Error());
    })
    .on('error', function(err) {
      console.log(err); // Error
    })
    .run(0);

API

piperline.create()

Creates a new pipeline runner.

.pipe(function(data, next, done))

Adds pipe for execution. Can be invoked only before or after execution.

data - any data passed from top pipes or run method.

next - callback which invokes next pipe or completes the execution. Any passed data to this callback will be transferred to the next pipe.

done - callback which terminates the execution of the whole pipeline.

Note: If Error object will be passed to one of these callbacks it will be treated as termination of execution and error event will be emitted with this object.

.run([data],[function(error, result)])

Builds and runs the execution.

data - any initial data which will be passed to the first pipe.

callback - callback which will be called when the execution is completed.

.isRunning()

Detects whether the pipeline is executing.

.on('run', function())

Fired every time when execution started and there are no already running in background.

.on('finish', function())

Fired every time when execution completed and there are no already running in background.

.on('done', function(result))

Fired for each successful execution.

.on('error', function(error))

Fired for each failed execution.