How do I get the Euler rotation of an object around the world axes

I want to get the rotation of the object around the world axes, Use the following code:

        let a = new THREE.Quaternion();
        let b = obj.getWorldQuaternion(a);
        let c1 = new THREE.Euler();
        const worldRotation = c1.setFromQuaternion(b);

The Euler angles(worldRotation) are the rotation values of the world axes or the rotation values of the object axes ?
A little confused, I hope you can help me out, thank you very much