Builder correctly generates void (self-closing) tags.

spec/stdlib/template/builder-spec.coffee

@@ -35,3 +35,7 @@ fdescribe "Builder", ->
       expect(fragment.attr('id')).toBe('foo')
       expect(fragment.attr('class')).toBe('bar')
 
+    it "can generate self-closing tags", ->
+      builder.tag 'br', id: 'foo'
+      expect(builder.toHtml()).toBe('<br id="foo">')
+

src/stdlib/template/builder.coffee

@@ -6,6 +6,18 @@ Text = require 'template/text'
 
 module.exports =
 class Builder
+  @elements:
+    normal: 'a abbr address article aside audio b bdi bdo blockquote body button
+      canvas caption cite code colgroup datalist dd del details dfn div dl dt em
+      fieldset figcaption figure footer form h1 h2 h3 h4 h5 h6 head header hgroup
+      html i iframe ins kbd label legend li map mark menu meter nav noscript object
+      ol optgroup option output p pre progress q rp rt ruby s samp script section
+      select small span strong style sub summary sup table tbody td textarea tfoot
+      th thead time title tr u ul video'.split /\s+/
+
+    void: 'area base br col command embed hr img input keygen link meta param
+      source track wbr'.split /\s+/
+
   constructor: ->
     @reset()
 
@@ -17,10 +29,19 @@ class Builder
 
   tag: (name, args...) ->
     options = @extractOptions(args)
-    @openTag(name, options.attributes)
-    options.content?()
-    @text(options.text) if options.text
-    @closeTag(name)
+
+    @document.push(new OpenTag(name, options.attributes))
+    if @elementIsVoid(name)
+      if (options.text? or options.content?)
+        throw new Error("Self-closing tag #{tag} cannot have text or content")
+    else
+      options.content?()
+      @text(options.text) if options.text
+      @document.push(new CloseTag(name))
+
+
+  elementIsVoid: (name) ->
+    _.contains(this.constructor.elements.void, name)
 
   extractOptions: (args) ->
     options = {}
@@ -31,12 +52,6 @@ class Builder
       options.attributes = arg if _.isObject(arg)
     options
 
-  openTag: (name, attributes) ->
-    @document.push(new OpenTag(name, attributes))
-
-  closeTag: (name) ->
-    @document.push(new CloseTag(name))
-
   text: (string) ->
     @document.push(new Text(string))