Where does on.exit() work?

on.exit() can be used on:

• Inside function bodies
• In testthat expressions
• In a reactive expression or observer

When does on.exit() run?

• In functions, the code in on.exit() runs after all the rest of the code has run.

• It runs even if there are errors / warnings.

• You can have multiple calls to on.exit() inside a function (use add = TRUE, so a call doesn’t overwrite an earlier one)