RIOT.JS - Observables

Quiz

Observables mechanism allows RIOT to send events from one tag to another. Following APIs are important to understand RIOT observables.

riot.observable(element) − Adds Observer support for the given object element or if the argument is empty a new observable instance is created and returned. After this the object is able to trigger and listen to events.

var EventBus = function(){
   riot.observable(this);
}

element.trigger(events) − Execute all callback functions that listen to the given event.

sendMessage() {
   riot.eventBus.trigger('message', 'Custom 10 Button Clicked!');    
}

element.on(events, callback) − Listen to the given event and execute the callback each time an event is triggered.

riot.eventBus.on('message', function(input) {      
   console.log(input);
});

Example

Following is the complete example.

custom10Tag.tag

<custom10Tag>
   <button onclick = {sendMessage}>Custom 10</button>
   <script>
      sendMessage() {
         riot.eventBus.trigger('message', 'Custom 10 Button Clicked!');    
      }
   </script>    
</custom10Tag>

custom11Tag.tag

<custom11Tag>
   <script>
      riot.eventBus.on('message', function(input) {      
         console.log(input);
      });
   </script>    
</custom11Tag>

custom9.htm

<html>
   <head>
      <script src = "https://cdnjs.cloudflare.com/ajax/libs/riot/3.13.2/riot+compiler.min.js"></script>
   </head>
   <body>
      <custom10Tag></custom10Tag>
      <custom11Tag></custom11Tag>
      <script src = "custom10Tag.tag" type = "riot/tag"></script>
      <script src = "custom11Tag.tag" type = "riot/tag"></script>
      <script>
         var EventBus = function(){
            riot.observable(this);
         }
         riot.eventBus = new EventBus();
         riot.mount("*");
      </script>
   </body>
</html>

This will produce following result −

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