Flow-JS Serial Sum Example 1

flow-serial-sum.js

var sys = require('sys');
var flow = require('./flow')

// this is a simple async function for adding an amount to a running total
var currentSum = 0;
function addToSum(amountToAdd, callback) {
	setTimeout(function() {
		currentSum += amountToAdd;
		callback();
	}, 100);
}

// this is the array we'd like to execute addToSum on in serial
var values = [5, 7, 1, 3];

// our flow needs one step per item in the values array
var defs = [];
values.forEach(function(val){
	defs.push(function(){
		addToSum(val, this);
	});
});

// and one more step when we're all done
defs.push(function(){
	sys.puts("The sum is finally: " + currentSum);
});

// execute the array of functions as a flow
flow.exec.apply(flow, defs);