code: function isNormalizedNormalAttribute(normal) {
        if (cachedData.attributes.has(normal)) {
          return false;
        }
  
        var v = new THREE.Vector3();
  
        for (var i = 0, il = normal.count; i < il; i++) {
          // 0.0005 is from glTF-validator
          if (Math.abs(v.fromArray(normal.array, i * 3).length() - 1.0) > 0.0005)
            return false;
        }
  
        return true;
      }
docs: Checks if normal attribute values are normalized.
  
  @param {THREE.BufferAttribute} normal
  @returns {Boolean}