js.plated_chunks.replace

value = plated_chunks.replace(str,dat)

Repeatedly call replace_once until all things that can expand, have expanded, or we ran out of sanity. Sanity is 100 levels of recursion, just to be on the safe side.

We then call a final replace_once with the lastpass flag set.

if dat is null then we use data pushed into the namespaces otherwise we will only use data available in dat.