Method clearCache

src/mapboxgl/overlay/GraphThemeLayer.js:364–367

* @function GraphThemeLayer.prototype.clearCache * @description 清除缓存。

()

     * @description  清除缓存。
     */
    clearCache() {
        this.cache = {};
        this.charts = [];
    }

    /**
     * @function GraphThemeLayer.prototype.removeFeatures