I'd usually understand this expressions to indicate that someone is impatient/excited about an upcoming event, wishing that it would be sooner.
Possibly in some situations it might mean someone has to leave before something happens, too. I'd probably rather use "until y happens" in that situation though, but I'm not sure if this is correct.
Duolingo sometimes translates it literally: no puedo esperar, e.g. here https://forum.duolingo.com/comment/5036 ... -everybody or here https://forum.duolingo.com/comment/4299 ... -the-party
Can the literal Spanish translation have both meaning?
On other occasions, they use
- estar impaciente
- esparar con ansias
And in the discussions and elsewhere I found
- no veo la hora de
- quiero que sea ya
- estar ansioso por
- morir por
Which of these would be idiomatic to express the first meaning?