async-machine v0.2.1

async-machine

minimal async finite state machine - tiny, powerfull, no dependencies, < 1kb min

• Example • Why • Limitations • API • License •

Example

	var machine = require('async-machine')
	function asyncAdd(v, cb) {
		siteTimeout(cb, 0, ++v)
	}
	function syncAdd(v, cb) {
		cb(++v)
	}
	function ondone(err, res) {
		if (res < 10) this[0](res)
		else console.log(res)
	}
	var sequence = machine([asyncAdd, syncAdd], ondone)
	machine[0](0) // 10!

Why

This is a proof of concept async flow control module. It is similar to async-waterfall but with additional functionalities similar to a finite state machine:

• a sequence is defined once but can be run many times
• ability to move forward or back in the sequence at anytime
• change in state cancels any pending callbacks

This allows the following uses:

• run a sequence in steps (similar to async-waterfall)
• run a sequence in a loop (async-while)
• join branches together to form a more complex finite state machine

Limitations

• Every sequence runs in a single direction
• No configuration
• No named stated. Only the index in the sequence

API

• machine(arrayOfAsyncFunctions, ondone) => return an array of functions
• arrayOfAsyncFunctions: any number of functions that pass a result to a callback f(a , b, function(err, res))
• callback: node style error-first function
• ondone: node style error-first function, internally binded to the array of steps

Any of the function returned in the array can be called at any time. Doing so cancels any pending callbacks. All callbacks and the final ondone function are binded to the sequence, allowing for conditionally loop back or jump forward anywhere in the sequence.

License

Released under the MIT License