node-pipeline

pipeline

Node.js module for simplifying and sequencing a number of dependent functions and callbacks.

Simple module to performing asynchronous inter-dependent series operations in node. Unlike other more complicated approaches, this is pure javascript and very small (~100 lines of code with comments).

Install

npm install node-pipeline

Simple example for calculating gratuity

This example is in the tests folder. It is basic and does not fully test all error conditions, but it is a good way to get the hang of the module.

var pipeline = require('node-pipeline'),
    pl = pipeline.create("Tax and Gratuity Calculator");
 
pl.on('end', function(err, results) {
    if (err) {
        console.log('Error in pipeline: ' + err);
    }
 
    console.log("Raw results" + JSON.stringify(results, 2) );
    process.exit();
});
 
 
pl.use(function(results, next) {
    var price = Number(results[0].price),
        taxrate = Number(results[0].taxrate);
 
    next(null, { tax : price * taxrate });
});
 
 
pl.use(function(results, next) {
    var price = Number(results[0].price),
        tax = Number(results[1].tax),
        gratuityrate = Number(results[0].gratuityrate);
 
    next(null, { gratuity : (price + tax) * gratuityrate }) 
});
 
 
pl.execute({
    currency: "USD",
    symbol: "$",
    price: argv.price || 0,
    taxrate: argv.tax || 0.0825,
    gratuityrate: argv.gratuity || "0.25"
});