Hacktiv
Implementation of the Functional reactive programming (FRP) paradigm, using reactive values. (Naive implementation of Meteor Tracker)
Used to keep track of variable values, and automaticaly execute code when a value change.
It automaticaly guess data dependencies, and when one of them change, every Hacktiv functions that depends on this data are retriggered to take consideration of the new values.
Install
$> npm install hacktiv
Quick Start
Will successively print 'test' and 'test2':
Hacktiv = require 'hacktiv' # Get a new reactive valuevalue = new Hacktiv.Value 'test' # The Hacktiv function will keep track of reactive values,# re-executing the function if any of the values or any# of their dependencies called inside have changedHacktiv -> # Calling the value without parameter returns the actual value console.log value() # [...] # Calling the value with a parameter update the underlying value and will reprintvalue 'test2'
Will successively print 'One Two' and 'One Three' :
value = new Hacktiv.Value 'One' value2 = new Hacktiv.Value 'Two' # Here if any of value or value2 change,# the console.log will reprint these two valuesHacktiv -> console.log value() + ' ' + value2() value2 'Three'
Will successively print 'test' and 'test2' :
value2 = new Hacktiv.Value 'test' # You can set reactive values as Functions or Objects.# They can reference other values, that will cause the Hacktiv function# to rerun if any of them changevalue = new Hacktiv.Value -> value2() Hacktiv -> console.log value() value2 'test2'
Status
You can check if you are in a watching context with Hacktiv.active
booleen
console.log Hacktiv.active #false Hacktiv -> console.log Hacktiv.active #true console.log Hacktiv.active #false
Stop watching
To stop watching, just get the handler back from your Hacktiv
function
and call its Stop()
function
value = new Hacktiv.Value 1 handler = Hacktiv -> console.log value() value2 'test2' handler.Stop() # This call will not refresh the functionvalue2 'test3'
You can temporarily stop watching with Hacktiv.DontWatch() :
Hacktiv -> Hacktiv.DontWatch -> # Here values are not monitored
Playing with the Dependency object
Will successively print [], ['test1'] and ['test1', 'test2'] :
Hacktiv = require 'hacktiv' class List extends Hacktiv.Dependency tasks: [] AddTask: (task) -> @tasks.push task @_Changed() Send: -> @_Depends() @tasks list = new List Hacktiv -> # Replace this with a websocket or a stream console.log list.Send() list.AddTask 'test1'list.AddTask 'test2'
Limits
When multiples Hacktiv functions run simultaneously, dependencies may not be correctly guessed cause of the global bus event 'depends', catched by every Computations
API
Hacktiv
The Hacktiv is the main function, taking track of every computations.
- Hacktiv(function)
- Add a new Computation with the given function
Computation
-
constructor(function)
- Start recording, Run the function, Stop recording.
-
StartRecord()
- Keep track of every Dependencies that run their _Depends() call
-
StopRecord()
- Stop recording for Dependencies
Dependency
-
constructor()
- Set the unique id for the dependency
-
_Depends()
- Send a global event to tell current recording Computation that a value has been accessed.
-
_Changed()
- Send a localised event to each Computations that have catched the Dependency that a value has changed.
Value
Is a function that take one argument.
- With argument: Setter
- Without argument: Getter
TODO
- Jail the Computation Record methods to avoir Dependencies collisions
- Provide methods to stop watching
Changelog
- Simplified syntax for Value. Now useable directly as function taking no parameter for Get and taking one for Set