# MapGIS Client for JavaScript API

Cesium MapboxGL Leaflet OpenLayers
API文档

    import { Collection, Evented, Zondy } from '../../../base'
    import { defaultValue, getGUID } from '../../../util'
    import { LayerType } from '../../../base/enum'

    /**
     * 子图层基类
     * @class SubLayer
     * @moduleEX LayerManagerModule
     * @extends Evented
     * @param {Object} options 构造参数
     * @param {String} [options.id] 图层id，不给则生成随机id
     * @param {Layer} [options.layer] 父图层对象
     * @param {Array} [options.sublayers = []] 包含的子图层对象
     * @param {String} [options.title] 图层名称
     * @param {Boolean} [options.visible] 图层可见性
     */
    class SubLayer extends Evented {
      constructor(options) {
        super(options)
        options = defaultValue(options, {})

        /**
         * 图层id，不给则生成随机id
         * @member {String} SubLayer.prototype.id
         */
        this.id = defaultValue(options.id, getGUID())
        /**
         * 父图层对象
         * @member {Layer} SubLayer.prototype.layer
         */
        this.layer = defaultValue(options.layer, undefined)
        /**
         * 包含的子图层对象
         * @member {Array} SubLayer.prototype.sublayers
         */
        this.sublayers = defaultValue(options.sublayers, new Collection())
        /**
         * 图层名称
         * @member {String} SubLayer.prototype.title
         */
        this.title = defaultValue(options.title || options.layerName, undefined)
        /**
         * 图层可见性
         * @member {Boolean} SubLayer.prototype.visible
         */
        // eslint-disable-next-line no-nested-ternary
        this._visible = options.hasOwnProperty('visible')
          ? options.visible
          : options.hasOwnProperty('isVisible')
          ? options.isVisible
          : true
      }

      /**
       * @description 转换为json对象
       * @return {Object} json对象
       */
      toJSON() {
        const _sublayers = []
        this.sublayers.forEach(function (sublayer) {
          _sublayers.push(sublayer.toJSON())
        })

        return {
          id: this.id,
          sublayers: _sublayers,
          title: this.title,
          visible: this.visible
        }
      }

      /**
       * @description 克隆方法
       * @return {SubLayer} 图层
       */
      clone() {
        return new SubLayer(this.toJSON())
      }
    }

    Object.defineProperties(SubLayer.prototype, {
      /**
       * 子图层显示或隐藏
       * @member {Boolean} SubLayer.prototype.visible
       */
      visible: {
        get() {
          return this._visible
        },
        set(value) {
          this._visible = value
          // 更新子图层
          if (this.layer && this.layer.refresh) {
            switch (this.layer.type) {
              case LayerType.igsMapImage:
                this.layer._setLayers()
                this.layer.refresh()
                break
              default:
                break
            }
          }
        }
      }
    })

    Zondy.Layer.SubLayer = SubLayer
    export default SubLayer

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