code: function GLTFParser( json, extensions, options ) {
  
      this.json = json || {};
      this.extensions = extensions || {};
      this.options = options || {};
  
      // loader object cache
      this.cache = new GLTFRegistry();
  
      // BufferGeometry caching
      this.primitiveCache = [];
  
      this.textureLoader = new THREE.TextureLoader( this.options.manager );
      this.textureLoader.setCrossOrigin( this.options.crossOrigin );
  
      this.fileLoader = new THREE.FileLoader( this.options.manager );
      this.fileLoader.setResponseType( 'arraybuffer' );
  
  }
docs: /* GLTF PARSER