Add IsEmpty; Publish 0.8.1

CHANGELOG.md

@@ -5,6 +5,7 @@
 FEATURES:
 
  - [common] Error.Error() includes cause
+ - [common] IsEmpty() for 0 length
 
 ## 0.8.0 (develop branch)
 

common/nil.go

@@ -16,3 +16,14 @@ func IsTypedNil(o interface{}) bool {
 		return false
 	}
 }
+
+// Returns true if it has zero length.
+func IsEmpty(o interface{}) bool {
+	rv := reflect.ValueOf(o)
+	switch rv.Kind() {
+	case reflect.Array, reflect.Chan, reflect.Map, reflect.Slice, reflect.String:
+		return rv.Len() == 0
+	default:
+		return false
+	}
+}