Is there an app to log “avoided spending”

[Fleabag123]

Just that really. I’d like an app to be able to log when I didn’t give into an impulse purchase/weekday takeaway or whatever. I think it would be motivating to see this build up across the month & be able to judge how much I’ve avoided spending.
Is anyone aware of such an app? I know I could do a spreadsheet but clearly I’m basic and motivated by shiny apps with bright colours!
Thanks

Could you move the money to a savings account instead of purchasing whatever it was?

That could work... I didn’t think of that.
I have Monzo which rounds up to saving account, could create an extra pot for “impulse saves”