access to the mpu 5060 array

Uh?

If you're talking about the mpu6050, that function returns an array with three members.

(this code isn't tested, ofc - I don't have that part)

var mpu=require("MPU6050").connect();
var t = mpu.getDegreesPerSecond();
if (t[1] > some_number ) { //t[1] is the second member of the array, hence Y axis
console.log("Wheee! y rotation rate is "+t[1].toString());
} else { 
console.log("Booo! y rotation rate is only "+t[1].toString());
}