I used the word "intended" behavior, because that is the behavior im looking for, but I may not be expressing it correctly in Svelte. It may not be the expected behavior of the code.

The intended behavior for the code snippet above is to reactively update b when a changes allows b temporarily go "out-of-sync" of a when calling update, setting b to 42 in this case, b is not always a * 2 however, if a changes again, b will be updated back to a * 2, instead of staying at 42

This is the intended behavior.