openlayers 给Feature提供修改撤销功能

最近在开发燃气管道布线gis系统，需要用到openlayers，功能需要自己做一个撤销的功能，openlayers API找了一圈没有发现有提供相应的api，于是自己利用栈的天然先进后出机制实现了一个。

 

撤销功能主要通过一个栈来实现的：

undoStack: [] // 撤回栈

当修改事件发生时，保存原来的Feature到栈中

modify.on('modifystart', (evt) => {
      var item = evt.features.item(0)
      var feature = new Feature()
      feature.setGeometry(item.getGeometry().clone())
      feature.setGeometryName(item.getGeometryName())
      feature.setStyle(item.getStyle())
      feature.ol_uid = item.ol_uid
      this.undoStack.push(feature)
    })

当点击了Undo按钮后，pop弹出栈顶的Feature，通过ol_uid把图层的修改后的feature给删除，然后把弹出的栈顶的feature添加进图层即可实现undo

undoClick () { // 撤回上一步修改操作
      let feature = this.undoStack.pop()
      console.log(feature.ol_uid)
      let findFeatureByUid1 = this.findFeatureByUid(feature.ol_uid)
      let source = this.map.getLayers().getArray()[0].getSource()
      source.removeFeature(findFeatureByUid1)
      console.log(feature)
      source.addFeature(feature)
    },
    findFeatureByUid (uid) {
      let source = this.map.getLayers().getArray()[0].getSource()
      let featureByUid = source.getFeatureByUid(uid)
      return featureByUid
    }