small pubsub - (maybe `call` api would be better finally...)

pubsub.js

var cache = {};

var pubsub = {
    publish: function(channel, args) {
        if (!cache[channel]) {
            return;
        }

        var stack = cache[channel];

        for (var i = 0, l = stack.length; i < l; i++) {
            var token = stack[i];
            token.callback.apply(token.ctx, args);
        }
    },

    subscribe: function(channel, callback, ctx) {
        if (!cache[channel]) {
            cache[channel] = [];
        }

        var token = {
            channel: channel,
            callback: callback,
            ctx: (ctx || {})
        };

        cache[channel].push(token);

        return token;
    },

    unsubscribe: function(token) {
        var stack = cache[token.channel];

        for (var i = 0, l = stack.length; i < l; i++) {
            var cachedToken = stack[i];

            if (
                cachedToken.callback === token.callback &&
                cachedToken.ctx === token.ctx
            ) {
                stack.splice(i, 1);
                return;
            }
        }
    },
    
    // @TODO : remove all handlers associated to the ctx
    removeHandlers: function(ctx) {}
}