- return 0s for offset() when element is not found

bonzo.js

@@ -34,6 +34,7 @@
     , uidList = []
     , uuids = 0
     , digit = /^-?[\d\.]+$/
+    , dattr = /^data-(.+)$/
     , px = 'px'
     , setAttribute = 'setAttribute'
     , getAttribute = 'getAttribute'
@@ -79,6 +80,23 @@
     })
   }
 
+  function decamelize(s) {
+    return s ? s.replace(/([a-z])([A-Z])/g, '$1-$2').toLowerCase() : s
+  }
+
+  function data(el) {
+    el[getAttribute]('data-node-uid') || el[setAttribute]('data-node-uid', ++uuids)
+    uid = el[getAttribute]('data-node-uid')
+    return uidList[uid] || (uidList[uid] = {})
+  }
+
+  function dataValue(d) {
+    try {
+      return d === 'true' ? true : d === 'false' ? false : d === 'null' ? null : !isNaN(d) ? parseFloat(d) : d;
+    } catch(e) {}
+    return undefined
+  }
+
   function isNode(node) {
     return node && node.nodeName && node.nodeType == 1
   }
@@ -232,11 +250,11 @@
       }
 
     , first: function () {
-        return bonzo(this[0])
+        return bonzo(this.length ? this[0] : [])
       }
 
     , last: function () {
-        return bonzo(this[this.length - 1])
+        return bonzo(this.length ? this[this.length - 1] : [])
       }
 
     , html: function (h, text) {
@@ -441,6 +459,12 @@
             xy(el, x, y)
           })
         }
+        if (!this[0]) return {
+            top: 0
+          , left: 0
+          , height: 0
+          , width: 0
+        }
         var el = this[0]
           , width = el.offsetWidth
           , height = el.offsetHeight
@@ -515,19 +539,20 @@
       }
 
     , data: function (k, v) {
-        var el = this[0], uid, o
+        var el = this[0], uid, o, m
         if (typeof v === 'undefined') {
-          el[getAttribute]('data-node-uid') || el[setAttribute]('data-node-uid', ++uuids)
-          uid = el[getAttribute]('data-node-uid')
-          uidList[uid] || (uidList[uid] = {})
-          return uidList[uid][k]
+          o = data(el)
+          if (typeof k === 'undefined') {
+            each(el.attributes, function(a) {
+              (m = (''+a.name).match(dattr)) && (o[camelize(m[1])] = dataValue(a.value))
+            })
+            return o
+          } else {
+            return typeof o[k] === 'undefined' ?
+              (o[k] = dataValue(this.attr('data-' + decamelize(k)))) : o[k]
+          }
         } else {
-          return this.each(function (el) {
-            el[getAttribute]('data-node-uid') || el[setAttribute]('data-node-uid', ++uuids)
-            uid = el[getAttribute]('data-node-uid')
-            o = uidList[uid] || (uidList[uid] = {})
-            o[k] = v
-          })
+          return this.each(function (el) { data(el)[k] = v })
         }
       }