grammar - だったら as an interjection

だったらさ！

だった is the completed tense of だ, ら is a rough indicator, and さ is an assertion. The completed existential verb with the rough indicator would seem to say something like "Things having been like so, indicates...", or "If that's the case, then..."

Would the assertion change it to something like "It is indicated that things are like so!" or "It is the case!"?

Answer

(だったら means "if it is, then".)

さ as in だったらさ is never a sentence ending particle. So it's always a filler.

さ as a sentence ender can appear (1) after a terminal form of verbs or adjectives, and (2) after a noun in the position of the predicate.

e.g. (1) なんとか なるさ。 (2) （私は）探偵さ。