Does Nodejs cache local variables?

If anyone is familiar with Java, Java has volatile modifier, which doesn't allow JVM to create a local copy of variables. This concept is important in the context of a multi-threaded environment of Java. I know that Nodejs is a single thread environment. It queued up a resource blocked task and executes a CPU-waiting task. Since there is only one thread and no-lock or thread-waiting concept is present, there doesn't seem to be a necessity of creating multiple local copies of a variable. Is there any local variable cache in Nodejs? And, if there is what is its use?