Added IsTimingFunctionValid function

CHANGELOG.md

@@ -5,7 +5,7 @@
 * Added "overflow", "arrow", "arrow-align", "arrow-size", "arrow-width", and "arrow-offset" properties 
 * Added "@ruiArrowSize" and "@ruiArrowWidth" constants to the default theme
 * Added Transition, Transitions, and SetTransition functions to the ViewStyle interface
-* Added GetOverflow, and GetTransitions functions
+* Added GetOverflow, IsTimingFunctionValid, and GetTransitions functions
 * Changed GetTransition functions
 
 # v0.8.0

animation.go

@@ -493,19 +493,22 @@ func (animation *animationData) writeTransitionString(tag string, buffer *string
 
 func (animation *animationData) timingFunctionCSS(session Session) string {
 	if timingFunction, ok := stringProperty(animation, TimingFunction, session); ok {
-		if timingFunction, ok = session.resolveConstants(timingFunction); ok && validateTimingFunction(timingFunction) {
+		if timingFunction, ok = session.resolveConstants(timingFunction); ok && IsTimingFunctionValid(timingFunction, session) {
 			return timingFunction
 		}
 	}
 	return ("ease")
 }
 
-func validateTimingFunction(timingFunction string) bool {
+// IsTimingFunctionValid returns "true" if the "timingFunction" argument is the valid timing function.
+func IsTimingFunctionValid(timingFunction string, session Session) bool {
 	switch timingFunction {
 	case "", EaseTiming, EaseInTiming, EaseOutTiming, EaseInOutTiming, LinearTiming:
 		return true
 	}
 
+	if timingFunc, ok := session.resolveConstants(timingFunction); ok {
+		timingFunction = timingFunc
 		size := len(timingFunction)
 		if size > 0 && timingFunction[size-1] == ')' {
 			if index := strings.IndexRune(timingFunction, '('); index > 0 {
@@ -528,6 +531,7 @@ func validateTimingFunction(timingFunction string) bool {
 				}
 			}
 		}
+	}
 
 	return false
 }

app_styles.css

@@ -59,7 +59,6 @@ ul:focus {
   outline: none;
 }
 
-
 .ruiRoot {
   position: absolute;
   top: 0px;