Reactive Programming is programming with (asynchronous) data streams
Anything can be a stream:
variables
events
data structures
etc
Anything can be a stream:
variables
events
data structures
etc
Pure Functions
Pure Functions
The function always evaluates the same result value given the same argument value(s)
Evaluation of the result does not cause any side effects, such as mutation of mutable objects or output to I/O devices.
Monads
Monads
come from Category Theory
encapsulate values of particular data type
join simple components in robust ways
are used to build pipelines that process data in a series of steps
contain additional processing rules for each step
Monads in JS (1)
function unit(value) {}
//returns a monad that contains the value
function bind(monad, function (value)) {}
//returns a monad containing the result of the function
//applied to the value of the monad
Monad Laws
Left identity: Creating a monad with 'a' and binding it with 'f' is the same as calling 'f(a)' bind(unit(x), f) ==== f(x)
Right identity: Binding the unit function on a monad returns the same monad bind(monad, unit) ==== monad
Associativity bind(bind(m, f), g) ==== bind(m, x ⇒ bind(f(x), g))
Container
function _Container(val) {
this._val = val;
}
_Container.prototype.map = function(f) {
return Container(f(this._val));
};
var Container = function(val) {
return new _Container(val);
};
