tabs.stache

tabs.stache

<can-component tag='can-tabs'>
  <style type='less'>
    	margin-top: 20px;
	button {clear: both;}
	ul {
	    padding: 0px; margin: 0px;
	}
	ul:after  { content: "."; display: block; height: 1px; clear: both; visibility: hidden; }
	ul { display: inline-block; }
	li {
	    float: left;
	    padding: 10px;
	    background-color: #F6F6F6;
	    list-style: none;
	    margin-left: 10px;
	    color: #1C94C4;
	    font-weight: bold;
	    text-decoration: none;
	}
	li.active {
	    color: #F6A828;
	    cursor: default;
	}
	can-panel {
   
	    clear: both;
	    display: block;
	}
  </style>
  <template type='text/stache'>
    <ul>
      {{#panels}}
        <li {{#isActive}}class='active'{{/isActive}} 
        	can-click='makeActive'>
	    	  {{title}}
    	</li>
      {{/panels}}
    </ul>
    <content></content>
  </template>
  <scope>
    import can from "can";
    import "can-panel.stache!"
    export default can.Map.extend({
	// Contains a list of all panel scopes within the
	// tabs element.
	panels: [],
	// When a `<panel>` element is inserted into the document,
	// it calls this method to add the panel's scope to the
	// panels array.
	addPanel: function(panel){
		// If this is the first panel, activate it.
		if( this.attr("panels").length === 0 ) {
			this.makeActive(panel);
		} 
		this.attr("panels").push(panel);
	},
	// When a `<panel>` element is removed from the document,
	// it calls this method to remove the panel's scope from
	// the panels array.
	removePanel: function(panel){
		var panels = this.attr("panels");
		can.batch.start();
		panels.splice(panels.indexOf(panel),1);
		// if the panel was active, make the first item active
		if(panel === this.attr("active")){
			if(panels.length){
				this.makeActive(panels[0]);
			} else {
				this.removeAttr("active")
			}
		}
		can.batch.stop()
	},
	makeActive: function(panel){
		this.attr("active",panel);
		this.attr("panels").each(function(panel){
			panel.attr("active", false)
		});
		panel.attr("active",true);
		
	},
	// this is scope, not mustache
	// consider removing scope as arg
	isActive: function( panel ) {
		return this.attr('active') == panel;
	}
    });
  </scope>
  <events>
     export default {}
  </events>
  <helpers>
     export default {}
  </helpers>
</can-component>

This is a wonderful, fantastic, (insert more compliments here) example! If I could make a few suggestions.

1. In the scope tag, I would replace the export default can.Map.extend with just export default {.
   CanJS itself could call can.Map.extend with whatever is exported from scope tag and decrease the potential of questions from new developers. On the flip side, increases the perception of "framework magic", because we are hiding some of the implementation details.
2. Remove the need to add export default {} in the events and helpers tags. If those tags don't exist, or the tags exist but are empty, we could assign an empty object.