stalker-pattern

Stalker-pattern is a Javascript pattern with a promise-like syntax streaming but in which the whole stream is re-triggerable like an event. Additionally it also supports synchronous triggering.

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API

A basic notion of Promises will help you easily understand this pattern.

Basics

var Stalker = require('stalker-pattern');
 
var myStalker = new Stalker(function(trigger){
  trigger("hi!");
});
 
myStalker.follow(function(result){
  console.log(result); //prints "hi!"
});
 

Chaining stalkers

var myStalker = new Stalker(function(trigger){
 
  trigger(new Stalker(function(t){
    t("More complex");
 
    setTimeout(function(){
      t("Async");
    })
  }));
 
}).follow(function(result){
 
  return new Stalker(function(t2){
    t2(result+" hi!");
  });
 
}).follow(function(result){
 
  // prints "More complex hi!",
  // and then on next tick prints "Async hi!"
  console.log(result);
 
});
 

Piping only a few occurrences

new Stalker(function(trigger){
 
  trigger(1);
  trigger(2);
  trigger(3);
  trigger(4);
 
}).from(1).to(3).follow(function(number){
 
  console.log(number); //prints 1,2,3
  return number;
 
}).the(2).follow(function(number){
 
  console.log(number); //prints 2
  return number;
 
}).first().follow(function(number){
 
  console.log(number); //prints 2
 
});
 
//stack prints:
//1, 2, 3, 2, 2
 

Note: In the case above "1","2","3" all fire in the first follow() before "2" is propagated down to the 2nd follow(). This is the default behaviour of Stalker for syncrounous triggering