user2167582
user2167582

Reputation: 6378

Is there a way to bind events to regular objects in javascript?

as subject states, I want to attach events to my objects and trigger its action at future so I can do asynchronous stuff without callbacks and Qs.

I dont want to attach & pollute any particular DOM or the document.

Upvotes: 2

Views: 45

Answers (1)

Krzysztof Safjanowski
Krzysztof Safjanowski

Reputation: 7438

Publish / Subscribe pattern

var utils = utils || {};
utils.publishSubscribe = (function() {

    var publishSubscribe = {};

    // Storage for topics that can be broadcast 
    // or listened to
    var topics = {};

    // An topic identifier
    var subUid = -1;

    // Publish or broadcast events of interest
    // with a specific topic name and arguments
    // such as the data to pass along
    publishSubscribe.publish = function( topic, args ) {

        if ( !topics[topic] ) {
            return false;
        }

        var subscribers = topics[topic],
            len = subscribers ? subscribers.length : 0;

        while (len--) {
            subscribers[len].func( topic, args );
        }

        return this;
    };

    // Subscribe to events of interest
    // with a specific topic name and a
    // callback function, to be executed
    // when the topic/event is observed
    publishSubscribe.subscribe = function( topic, func ) {

        if (!topics[topic]) {
            topics[topic] = [];
        }

        var token = ( ++subUid ).toString();
        topics[topic].push({
            token: token,
            func: func
        });
        return token;
    };

    // Unsubscribe from a specific
    // topic, based on a tokenized reference
    // to the subscription
    publishSubscribe.unsubscribe = function( token ) {
        for ( var m in topics ) {
            if ( topics[m] ) {
                for ( var i = 0, j = topics[m].length; i < j; i++ ) {
                    if ( topics[m][i].token === token ) {
                        topics[m].splice( i, 1 );
                        return token;
                    }
                }
            }
        }
        return this;
    };

    return publishSubscribe;
}());

Usage

utils.publishSubscribe.subscribe( "inbox/newMessage", function( topic, data ) {
    console.log( "A new message was received: ", data );
})

utils.publishSubscribe.publish( "inbox/newMessage", [{
      sender: "[email protected]",
      body: "Hey there! How are you doing today?"
}]);

source: Addy Osmani – Learning JavaScript Design Patterns

Upvotes: 2

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