Wednesday, August 15th, 2007
Building an event-based Ajax application
Category: Dojo, JavaScript
If you have an application that uses devices like deferred loading, or “parse on demandâ€, wrapping it with an initializer helps keep it that way.
The final code example is:
JAVASCRIPT:
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acme.topic = function(){
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// current topic argument hash map
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this.current = {};
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};
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dojo.extend(acme.topic, {
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subscribe: function(topic, scope, method, acceptNull){
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var hdl = dojo.subscribe(topic, scope, method)
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//Initializer - called only once, on subscribe
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if(acceptNull || this.current[topic]){
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// Converting arg to a non-array if it is not a length> 1
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var a = this.current[topic];
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var arg = (a == null) ? null : (a.length == 1) ? a[0] : a;
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//NOTE! Only accepting string methods
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scope[method].call(scope, arg);
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}
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return hdl;
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},
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publish: function(topic, args){
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dojo.publish(topic, args);
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// Store published arg, in the event a subscribe is called later
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this.current[topic] = args;
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},
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unsubscribe: function(handle){
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// Pass-through. Could be called directly.
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dojo.unsubscribe(handle);
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}
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})
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