cesiumDemo/Source/Scene/QuadtreeTileLoadState.js

import freezeObject from '../Core/freezeObject.js';

    /**
     * The state of a {@link QuadtreeTile} in the tile load pipeline.
     * @exports QuadtreeTileLoadState
     * @private
     */
    var QuadtreeTileLoadState = {
        /**
         * The tile is new and loading has not yet begun.
         * @type QuadtreeTileLoadState
         * @constant
         * @default 0
         */
        START : 0,

        /**
         * Loading is in progress.
         * @type QuadtreeTileLoadState
         * @constant
         * @default 1
         */
        LOADING : 1,

        /**
         * Loading is complete.
         * @type QuadtreeTileLoadState
         * @constant
         * @default 2
         */
        DONE : 2,

        /**
         * The tile has failed to load.
         * @type QuadtreeTileLoadState
         * @constant
         * @default 3
         */
        FAILED : 3
    };
export default freezeObject(QuadtreeTileLoadState);