dart:developer

debugger function

bool debugger({bool when: true, String message })

If when is true, stop the program as if a breakpoint were hit at the following statement.

Returns the value of when. Some debuggers may display message.

NOTE: When invoked, the isolate will not return until a debugger continues execution. When running in the Dart VM the behaviour is the same regardless of whether or not a debugger is connected. When compiled to JavaScript, this uses the "debugger" statement, and behaves exactly as that does.

Source

external bool debugger({bool when: true, String message});