I'm guessing because .and is a function it can be used to pass into any higher order function. var x = [true, false, true, false]; x.reduce(and, true);

I'm guessing because .and is a function it can be used to pass into any higher order function. var x = [true, false, true, false]; x.reduce(and, true); // == false x.reduce(or, false); // == true