ch-7/labs-1

Hello everyone, I'm trying to make a code to pass in the labs-1 from chapter 7, but in the given code from the package, we have something like that:

Ok if we assume somehtings like that:
var brands = [ 'Boston Whaler','Chaparral','Grady-White','Lund','MasterCraft','Sea Ray' ] ( length = 6 ), when id is equal to 1 the output of the given code will be undefined because the 1 - 231 evaluates to a number that is less than 0 and the modulus of (-230 % brands.length) is -2, when node evaluates brands[-2] it awlays returns an undefined value.

Does this code is correct or am I missed something?