Javascript 3D Physics Tut 2 Move Ball

moveBall.js

function moveBall(){

    let scalingFactor = 20;

    let moveX =  moveDirection.right - moveDirection.left;
    let moveZ =  moveDirection.back - moveDirection.forward;
    let moveY =  0; 

    if( moveX == 0 && moveY == 0 && moveZ == 0) return;

    let resultantImpulse = new Ammo.btVector3( moveX, moveY, moveZ )
    resultantImpulse.op_mul(scalingFactor);

    let physicsBody = ballObject.userData.physicsBody;
    physicsBody.setLinearVelocity( resultantImpulse );

}