refactor

set.go

@@ -1,10 +1,12 @@
 package gocache
 
+import "time"
+
 func (cache *myCache) Set(key string, data interface{}) error {
 	cache.mutex.Lock()
 	defer cache.mutex.Unlock()
 
-	value := newValue(key, data, cache.expireAfter)
+	value := newValue(key, data, time.Now().UnixNano()+cache.expireAfter)
 	cache.items[key] = value
 
 	return nil

value.go

@@ -1,7 +1,5 @@
 package gocache
 
-import "time"
-
 type value struct {
 	key        string
 	data       interface{}
@@ -12,6 +10,6 @@ func newValue(key string, data interface{}, expiration int64) *value {
 	return &value{
 		key:        key,
 		data:       data,
-		expiration: time.Now().UnixNano() + expiration,
+		expiration: expiration,
 	}
 }