'debugger' called from the right-hand side of IDE panel?

Sun 2021.03.14

It is likely that there is a small amount of delay during the upload that Espruino requires to unpack and manage memory, and the debugger becomes initialized after the testDebugger() function call.

By placing a small delay within your snippet, it is possible to launch immediately after the upload is complete.

function testDebugger() {
  debugger;
}

intervalID = setInterval( function (){

    testDebugger();
    
  }, 1500);

Edit:
In my haste to reveal a working solution, I actually needed to test some more. The use of
L5 timeoutID = setTimeout( function (){ as pointed out in post #3 is a better choice to make just one and only one call to invoke the debugger

Result:

>
        debugger;
        ^
debug>