Best practice: value declaration vs using .state directly

Setup, Configuration and Use Scripts & Rules
1

Hey there,
as far as I know, there are two ways of using item values in rules: value declaration and using .state directly (see example below).

rule "example"
when 
   Item x changed
then

   val y = item_y.state [as x]
   if (y == 1) {
   <snip>

   if (item_y.state == 1) {
   <snip>

Value declaration might be faster when a value is used multiple times, but the differences were not really measurable on my hardware (Intel NUC with i3-Processor).

Are there any pros and cons about which option to choose? Are there some preferred situations for either ones?

Kind regards!

2

It’s worth considering what happens if the Item state changes during your rule execution.
Most often the safest course where that might happen is to “capture” the current state in a var= or val= at the head of the rule code.

3

Use .state so it’s always up to date. There’s absolutely no point in optimizing speed.