Memoize values used more than once during the template function execution

[Gr8Gatsby]

SOMA#255

Migrated issue

notes:

When accessing a getter, we can memoize the value produced by the getter and tied that value to the reactive objects accessed from within the getter, and only call the getter again if any of those reactive objects changes.

VUE implements some of this, and this will also prevent people doing premature optimizations when the getter is suppose to do complex operations.

[caridy]

If we are going to lift the restriction of mutations of non-decorated fields during rendering, we should make sure that we implement this, otherwise something like: <template>{cacheCounter}:{cacheCounter}</template> might output something like "1:2" instead of "1:1", without the memoization process.

[uip-robot-zz]

This issue has been linked to a new work item: W-9479534