publish/subscribe, or pubsub

annotated.js

function(
  a, // the subscription object
  b, // the current event number
  c  // (placeholder)
){
  return {            // return an object, with
    pub: function(    // a "pub" function that takes
      d,              // a channel name and
      e               // a message value,
    ){                // and
      for(            // for each
        c             // subscriber
        in a          // in the subscription object,
      ) if (          // if
        c             // its name, with the event number discarded
          .split      // by splitting it
          ("-")       // with a hyphen and
          [0]         // taking only the first part,
          == d        // is equal to the published channel
      ) a[c](e)       // call the subscriber. and if
        !== !1 ||     // the value returned is false
        delete a[c]   // unsubscribe by removing the subscriber, and
    },
    
    sub: function(    // a "sub" function that takes
      d,              // a channel name and
      e               // a subscriber function
    ){                // and,
      a[              // on the subscriptions object,
        d +           // sets the name of the channel appended with 
        --b           // a hyphen and the decremented event number, to 
      ] = e           // the function passed.
    }
  }
}(    // auto-run with
  {}, // the subscription object
  0   // and event id.
)

index.js

function(a,b,c){return{pub:function(d,e){for(c in a)if(c.split("-")[0]==d)a[c](e)!==!1||delete a[c]},sub:function(d,e){a[d+--b]=e}}}({},0)

LICENSE.txt

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
                    Version 2, December 2004

 Copyright (C) 2011 Jed Schmidt <http://jed.is>

 Everyone is permitted to copy and distribute verbatim or modified
 copies of this license document, and changing it is allowed as long
 as the name is changed.

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

  0. You just DO WHAT THE FUCK YOU WANT TO.

package.json

{
  "name": "pubsub",
  "keywords": [ "pubsub", "observer", "publish", "subscribe" ]
}

test.js

// Define the pubsub object, which provides the "pub" and "sub" methods.
var pubsub = function(a,b,c){return{pub:function(d,e){for(c in a)if(c.split("-")[0]==d)a[c](e)!==!1||delete a[c]},sub:function(d,e){a[d+--b]=e}}}({},0)

// Subscribe to the "random" channel, returning false to unsubscribe.
pubsub.sub("random", function( msg ) {
  console.log("this is called once: " + msg);
  return false;
})

// Subscribe to the "random" channel, and always renew.
pubsub.sub("random", function( msg ) {
  console.log("this is called forever: " + msg);
})

// Subscribe to the "random" channel, but set an
// expiration date 5 seconds in the future, and
// unsubscribe when the date is reached.
expiration = +new Date + 5000
pubsub.sub("random", function( msg ) {
  console.log( "this is called for 5 seconds: " + msg);
  return +new Date < expiration;
})

// Publish a random number between 1 and 10 to
// the "random" channel every second.
setInterval( function(){ pubsub.pub( "random", 0|Math.random()*10 ) }, 1000 )