How to extend the Face class?

Hi, I tried to extend the Face class with the name property using prototype and also adding this property to the file in the threejs library but unfortunately all Faces have the same value after the merge operation. The value assigned in the constructor. Why is this happening?

Without providing some coding, it’s impossible to tell.

Example Code = function() {
var offset = new THREE.Vector3();
this.boundingBox.getCenter( offset ).negate();
this.translate( offset.x, offset.y, offset.z );
return offset; };