traffic-laser/src/graphic/History/Change.js

import { dataService } from "../Service/DataService";
import { roadService } from "../Service/RoadService";
import { historyUtil } from "./HistoryUtil";
import HistoryEvents from "../enum/HistoryEvents";
import { coordinate } from "../Coordinate";
import { mathUtil } from "../Util/MathUtil";
import Settings from "../Settings";

export default class Change {
  constructor() {
    this.lastData = {}; // 每次都是当前数据和lastData进行比较，一般在mouseDown的时候存储进来
    this.currentData = {}; // 当前的变化
  }

  // 保存当前记录
  saveCurrentInfo() {
    // this.lastData.roadPoints = JSON.parse(
    //   JSON.stringify(dataService.getRoadPoints())
    // );
    //this.lastData.roads = JSON.parse(JSON.stringify(dataService.getRoads()));
    this.lastData.lines = JSON.parse(JSON.stringify(dataService.getLines()));
    this.lastData.texts = JSON.parse(JSON.stringify(dataService.getTexts()));
    this.lastData.points = JSON.parse(JSON.stringify(dataService.getPoints()));

    this.lastData.curveLines = JSON.parse(
      JSON.stringify(dataService.getCurveLines())
    );
    this.lastData.curvePoints = JSON.parse(
      JSON.stringify(dataService.getCurvePoints())
    );

    this.lastData.circles = JSON.parse(
      JSON.stringify(dataService.getCircles())
    );
    this.lastData.elliptics = JSON.parse(
      JSON.stringify(dataService.getElliptics())
    );
    this.lastData.magnifiers = JSON.parse(
      JSON.stringify(dataService.getMagnifiers())
    );
    this.lastData.svgs = JSON.parse(JSON.stringify(dataService.getSVGs()));
    this.lastData.roadPoints = JSON.parse(
      JSON.stringify(dataService.getRoadPoints())
    );
    this.lastData.roadEdges = JSON.parse(
      JSON.stringify(dataService.getRoadEdges())
    );
    this.lastData.roads = JSON.parse(JSON.stringify(dataService.getRoads()));
    this.lastData.curveRoadPoints = JSON.parse(
      JSON.stringify(dataService.getCurveRoadPoints())
    );
    this.lastData.curveRoadEdges = JSON.parse(
      JSON.stringify(dataService.getCurveRoadEdges())
    );
    this.lastData.curveRoads = JSON.parse(
      JSON.stringify(dataService.getCurveRoads())
    );
    this.lastData.crossPoints = JSON.parse(
      JSON.stringify(dataService.getCrossPoints())
    );

    this.lastData.settings = JSON.parse(JSON.stringify(Settings));
  }

  operate() {
    //
    this.currentData = {};
    // this.compareRoads();
    this.comparePoints();
    this.compareLines();
    this.compareCurvePoints();
    this.compareCurveLines();
    this.compareCircles();
    this.compareElliptics();
    this.compareTexts();
    this.compareMagnifiers();
    this.compareSVGs();
    this.compareRoadPoints();
    this.compareRoadEdges();
    this.compareRoads();
    this.compareCurveRoadPoints();
    this.compareCurveRoadEdges();
    this.compareCurveRoads();
    this.compareCrossPoints();
    this.compareSettings();
    if (
      this.currentData.points.length == 0 &&
      this.currentData.lines.length == 0 &&
      this.currentData.curvePoints.length == 0 &&
      this.currentData.curveLines.length == 0 &&
      this.currentData.circles.length == 0 &&
      this.currentData.elliptics.length == 0 &&
      this.currentData.texts.length == 0 &&
      this.currentData.magnifiers.length == 0 &&
      this.currentData.roadPoints.length == 0 &&
      this.currentData.roadEdges.length == 0 &&
      this.currentData.roads.length == 0 &&
      this.currentData.curveRoadPoints.length == 0 &&
      this.currentData.curveRoadEdges.length == 0 &&
      this.currentData.curveRoads.length == 0 &&
      this.currentData.crossPoints.length == 0 &&
      this.currentData.settings
    ) {
      this.saveCurrentInfo();
      return false;
    }
    this.lastData = {};
    // 这里不能取this.records.length-1，因为可能撤销后操作，这时候应该是覆盖，而不是往后面添加
    return true;
  }

  comparePoints() {
    const points = dataService.getPoints();
    this.currentData.points = [];

    for (const key in points) {
      const point = points[key];
      // 不存在意味着增加
      if (!this.lastData.points[key]) {
        const item = {
          handle: HistoryEvents.AddPoint,
          point: historyUtil.getDataForPoint(point),
        };
        this.currentData.points.push(item);
      } else {
        const lastPoint = this.lastData.points[key];
        if (!historyUtil.isDifferentForPoints(point, lastPoint)) {
          delete this.lastData.points[key];
          continue;
        } else {
          const item = {
            handle: HistoryEvents.ModifyPoint,
            prePoint: historyUtil.getDataForPoint(lastPoint),
            curPoint: historyUtil.getDataForPoint(point),
          };
          this.currentData.points.push(item);
        }
      }
      delete this.lastData.points[key];
    }

    for (const key in this.lastData.points) {
      const item = {
        handle: HistoryEvents.DeletePoint,
        point: historyUtil.getDataForPoint(this.lastData.points[key]),
      };
      this.currentData.points.push(item);
    }
  }

  compareLines() {
    const lines = dataService.getLines();
    this.currentData.lines = [];

    for (const key in lines) {
      const line = lines[key];
      // 不存在意味着增加
      if (!this.lastData.lines[key]) {
        const item = {
          handle: HistoryEvents.AddLine,
          line: historyUtil.getDataForLine(line),
        };
        this.currentData.lines.push(item);
      } else {
        const lastLine = this.lastData.lines[key];
        if (!historyUtil.isDifferentForLines(line, lastLine)) {
          delete this.lastData.lines[key];
          continue;
        } else {
          const item = {
            handle: HistoryEvents.ModifyLine,
            preLine: historyUtil.getDataForLine(lastLine),
            curLine: historyUtil.getDataForLine(line),
          };
          this.currentData.lines.push(item);
        }
      }
      delete this.lastData.lines[key];
    }

    for (const key in this.lastData.lines) {
      const item = {
        handle: HistoryEvents.DeleteLine,
        line: historyUtil.getDataForLine(this.lastData.lines[key]),
      };
      this.currentData.lines.push(item);
    }
  }

  compareCurvePoints() {
    const curvePoints = dataService.getCurvePoints();
    this.currentData.curvePoints = [];

    for (const key in curvePoints) {
      const curvePoint = curvePoints[key];
      // 不存在意味着增加
      if (!this.lastData.curvePoints[key]) {
        const item = {
          handle: HistoryEvents.AddCurvePoint,
          curvePoint: historyUtil.getDataForCurvePoint(curvePoint),
        };
        this.currentData.curvePoints.push(item);
      } else {
        const lastCurvePoint = this.lastData.curvePoints[key];
        if (
          !historyUtil.isDifferentForCurvePoints(curvePoint, lastCurvePoint)
        ) {
          delete this.lastData.curvePoints[key];
          continue;
        } else {
          const item = {
            handle: HistoryEvents.ModifyCurvePoint,
            preCurvePoint: historyUtil.getDataForCurvePoint(lastCurvePoint),
            curCurvePoint: historyUtil.getDataForCurvePoint(curvePoint),
          };
          this.currentData.curvePoints.push(item);
        }
      }
      delete this.lastData.curvePoints[key];
    }

    for (const key in this.lastData.curvePoints) {
      const item = {
        handle: HistoryEvents.DeleteCurvePoint,
        curvePoint: historyUtil.getDataForCurvePoint(
          this.lastData.curvePoints[key]
        ),
      };
      this.currentData.curvePoints.push(item);
    }
  }
  compareCurveLines() {
    const curveLines = dataService.getCurveLines();
    this.currentData.curveLines = [];

    for (const key in curveLines) {
      const curveLine = curveLines[key];
      // 不存在意味着增加
      if (!this.lastData.curveLines[key]) {
        const item = {
          handle: HistoryEvents.AddCurveLine,
          curveLine: historyUtil.getDataForCurveLine(curveLine),
        };
        this.currentData.curveLines.push(item);
      } else {
        const lastCurveLine = this.lastData.curveLines[key];
        if (!historyUtil.isDifferentForCurveLines(curveLine, lastCurveLine)) {
          delete this.lastData.curveLines[key];
          continue;
        } else {
          const item = {
            handle: HistoryEvents.ModifyCurveLine,
            preCurveLine: historyUtil.getDataForCurveLine(lastCurveLine),
            curCurveLine: historyUtil.getDataForCurveLine(curveLine),
          };
          this.currentData.curveLines.push(item);
        }
      }
      delete this.lastData.curveLines[key];
    }

    for (const key in this.lastData.curveLines) {
      const item = {
        handle: HistoryEvents.DeleteCurveLine,
        curveLine: historyUtil.getDataForCurveLine(
          this.lastData.curveLines[key]
        ),
      };
      this.currentData.curveLines.push(item);
    }
  }

  compareTexts() {
    this.currentData.texts = [];
    const texts = dataService.getTexts();

    for (const key in texts) {
      const text = texts[key];
      const lastText = this.lastData.texts[key];

      // 不存在意味着增加
      if (!lastText) {
        const item = {
          handle: HistoryEvents.AddText,
          text: historyUtil.getDataForText(text),
        };
        this.currentData.texts.push(item);
      } else {
        if (!historyUtil.isDifferentForTexts(text, lastText)) {
          delete this.lastData.texts[key];
          continue;
        } else {
          const item = {
            handle: HistoryEvents.ModifyText,
            preText: historyUtil.getDataForText(lastText),
            curText: historyUtil.getDataForText(text),
          };
          this.currentData.texts.push(item);
        }
      }
      delete this.lastData.texts[key];
    }

    for (const key in this.lastData.texts) {
      const item = {
        handle: HistoryEvents.DeleteText,
        text: historyUtil.getDataForText(this.lastData.texts[key]),
      };
      this.currentData.texts.push(item);
    }
  }

  compareCircles() {
    const circles = dataService.getCircles();
    this.currentData.circles = [];

    for (const key in circles) {
      const circle = circles[key];
      // 不存在意味着增加
      if (!this.lastData.circles[key]) {
        const item = {
          handle: HistoryEvents.AddCircle,
          circle: historyUtil.getDataForCircle(circle),
        };
        this.currentData.circles.push(item);
      } else {
        const lastCircle = this.lastData.circles[key];
        if (!historyUtil.isDifferentForCircles(circle, lastCircle)) {
          delete this.lastData.circles[key];
          continue;
        } else {
          const item = {
            handle: HistoryEvents.ModifyCircle,
            preCircle: historyUtil.getDataForCircle(lastCircle),
            curCircle: historyUtil.getDataForCircle(circle),
          };
          this.currentData.circles.push(item);
        }
      }
      delete this.lastData.circles[key];
    }

    for (const key in this.lastData.circles) {
      const item = {
        handle: HistoryEvents.DeleteCircle,
        circle: historyUtil.getDataForCircle(this.lastData.circles[key]),
      };
      this.currentData.circles.push(item);
    }
  }

  compareElliptics() {
    const elliptics = dataService.getElliptics();
    this.currentData.elliptics = [];

    for (const key in elliptics) {
      const elliptic = elliptics[key];
      // 不存在意味着增加
      if (!this.lastData.elliptics[key]) {
        const item = {
          handle: HistoryEvents.AddElliptic,
          elliptic: historyUtil.getDataForElliptic(elliptic),
        };
        this.currentData.elliptics.push(item);
      } else {
        const lastElliptic = this.lastData.elliptics[key];
        if (!historyUtil.isDifferentForElliptics(elliptic, lastElliptic)) {
          delete this.lastData.elliptics[key];
          continue;
        } else {
          const item = {
            handle: HistoryEvents.ModifyElliptic,
            preElliptic: historyUtil.getDataForElliptic(lastElliptic),
            curElliptic: historyUtil.getDataForElliptic(elliptic),
          };
          this.currentData.elliptics.push(item);
        }
      }
      delete this.lastData.elliptics[key];
    }

    for (const key in this.lastData.elliptics) {
      const item = {
        handle: HistoryEvents.DeleteElliptic,
        elliptic: historyUtil.getDataForElliptic(this.lastData.elliptics[key]),
      };
      this.currentData.elliptics.push(item);
    }
  }

  compareMagnifiers() {
    const magnifiers = dataService.getMagnifiers();
    this.currentData.magnifiers = [];

    for (const key in magnifiers) {
      const magnifier = magnifiers[key];
      // 不存在意味着增加
      if (!this.lastData.magnifiers[key]) {
        const item = {
          handle: HistoryEvents.AddMagnifier,
          magnifier: historyUtil.getDataForMagnifier(magnifier),
        };
        this.currentData.magnifiers.push(item);
      } else {
        const lastMagnifier = this.lastData.magnifiers[key];
        if (!historyUtil.isDifferentForMagnifiers(magnifier, lastMagnifier)) {
          delete this.lastData.magnifiers[key];
          continue;
        } else {
          const item = {
            handle: HistoryEvents.ModifyMagnifier,
            preMagnifier: historyUtil.getDataForMagnifier(lastMagnifier),
            curMagnifier: historyUtil.getDataForMagnifier(magnifier),
          };
          this.currentData.magnifiers.push(item);
        }
      }
      delete this.lastData.magnifiers[key];
    }

    for (const key in this.lastData.magnifiers) {
      const item = {
        handle: HistoryEvents.DeleteMagnifier,
        magnifier: historyUtil.getDataForMagnifier(
          this.lastData.magnifiers[key]
        ),
      };
      this.currentData.magnifiers.push(item);
    }
  }

  compareSVGs() {
    this.currentData.svgs = [];
    const svgs = dataService.getSVGs();

    for (const key in svgs) {
      const svg = svgs[key];
      const lastSVG = this.lastData.svgs[key];

      // 不存在意味着增加
      if (!lastSVG) {
        const item = {
          handle: HistoryEvents.AddSVG,
          svg: historyUtil.getDataForSVG(svg),
        };
        this.currentData.svgs.push(item);
      } else {
        if (!historyUtil.isDifferentForSVGs(svg, lastSVG)) {
          delete this.lastData.svgs[key];
          continue;
        } else {
          const item = {
            handle: HistoryEvents.ModifySVG,
            preSVG: historyUtil.getDataForSVG(lastSVG),
            curSVG: historyUtil.getDataForSVG(svg),
          };
          this.currentData.svgs.push(item);
        }
      }
      delete this.lastData.svgs[key];
    }

    for (const key in this.lastData.svgs) {
      const item = {
        handle: HistoryEvents.DeleteSVG,
        svg: historyUtil.getDataForSVG(this.lastData.svgs[key]),
      };
      this.currentData.svgs.push(item);
    }
  }

  compareRoadPoints() {
    this.currentData.roadPoints = [];
    const roadPoints = dataService.getRoadPoints();

    for (const key in roadPoints) {
      const roadPoint = roadPoints[key];
      const lastRoadPoint = this.lastData.roadPoints[key];

      // 不存在意味着增加
      if (!lastRoadPoint) {
        const item = {
          handle: HistoryEvents.AddRoadPoint,
          roadPoint: historyUtil.getDataForRoadPoint(roadPoint),
        };
        this.currentData.roadPoints.push(item);
      } else {
        if (!historyUtil.isDifferentForRoadPoints(roadPoint, lastRoadPoint)) {
          delete this.lastData.roadPoints[key];
          continue;
        } else {
          const item = {
            handle: HistoryEvents.ModifyRoadPoint,
            preRoadPoint: historyUtil.getDataForRoadPoint(lastRoadPoint),
            curRoadPoint: historyUtil.getDataForRoadPoint(roadPoint),
          };
          this.currentData.roadPoints.push(item);
        }
      }
      delete this.lastData.roadPoints[key];
    }

    for (const key in this.lastData.roadPoints) {
      const item = {
        handle: HistoryEvents.DeleteRoadPoint,
        roadPoint: historyUtil.getDataForRoadPoint(
          this.lastData.roadPoints[key]
        ),
      };
      this.currentData.roadPoints.push(item);
    }
  }

  compareRoadEdges() {
    this.currentData.roadEdges = [];
    const roadEdges = dataService.getRoadEdges();

    for (const key in roadEdges) {
      const roadEdge = roadEdges[key];
      const lastRoadEdge = this.lastData.roadEdges[key];

      // 不存在意味着增加
      if (!lastRoadEdge) {
        const item = {
          handle: HistoryEvents.AddRoadEdge,
          roadEdge: historyUtil.getDataForRoadEdge(roadEdge),
        };
        this.currentData.roadEdges.push(item);
      } else {
        if (!historyUtil.isDifferentForRoadEdges(roadEdge, lastRoadEdge)) {
          delete this.lastData.roadEdges[key];
          continue;
        } else {
          const item = {
            handle: HistoryEvents.ModifyRoadEdge,
            preRoadEdge: historyUtil.getDataForRoadEdge(lastRoadEdge),
            curRoadEdge: historyUtil.getDataForRoadEdge(roadEdge),
          };
          this.currentData.roadEdges.push(item);
        }
      }
      delete this.lastData.roadEdges[key];
    }

    for (const key in this.lastData.roadEdges) {
      const item = {
        handle: HistoryEvents.DeleteRoadEdge,
        roadEdge: historyUtil.getDataForRoadEdge(this.lastData.roadEdges[key]),
      };
      this.currentData.roadEdges.push(item);
    }
  }

  compareRoads() {
    this.currentData.roads = [];
    const roads = dataService.getRoads();

    for (const key in roads) {
      const road = roads[key];
      const lastRoad = this.lastData.roads[key];

      // 不存在意味着增加
      if (!lastRoad) {
        const item = {
          handle: HistoryEvents.AddRoad,
          road: historyUtil.getDataForRoad(road),
        };
        this.currentData.roads.push(item);
      } else {
        if (!historyUtil.isDifferentForRoads(road, lastRoad)) {
          delete this.lastData.roads[key];
          continue;
        } else {
          const item = {
            handle: HistoryEvents.ModifyRoad,
            preRoad: historyUtil.getDataForRoad(lastRoad),
            curRoad: historyUtil.getDataForRoad(road),
          };
          this.currentData.roads.push(item);
        }
      }
      delete this.lastData.roads[key];
    }

    for (const key in this.lastData.roads) {
      const item = {
        handle: HistoryEvents.DeleteRoad,
        road: historyUtil.getDataForRoad(this.lastData.roads[key]),
      };
      this.currentData.roads.push(item);
    }
  }

  compareCurveRoadPoints() {
    this.currentData.curveRoadPoints = [];
    const curveRoadPoints = dataService.getCurveRoadPoints();

    for (const key in curveRoadPoints) {
      const curveRoadPoint = curveRoadPoints[key];
      const lastCurveRoadPoint = this.lastData.curveRoadPoints[key];

      // 不存在意味着增加
      if (!lastCurveRoadPoint) {
        const item = {
          handle: HistoryEvents.AddCurveRoadPoint,
          curveRoadPoint: historyUtil.getDataForCurveRoadPoint(curveRoadPoint),
        };
        this.currentData.curveRoadPoints.push(item);
      } else {
        if (
          !historyUtil.isDifferentForCurveRoadPoints(
            curveRoadPoint,
            lastCurveRoadPoint
          )
        ) {
          delete this.lastData.curveRoadPoints[key];
          continue;
        } else {
          const item = {
            handle: HistoryEvents.ModifyCurveRoadPoint,
            preCurveRoadPoint:
              historyUtil.getDataForCurveRoadPoint(lastCurveRoadPoint),
            curCurveRoadPoint:
              historyUtil.getDataForCurveRoadPoint(curveRoadPoint),
          };
          this.currentData.curveRoadPoints.push(item);
        }
      }
      delete this.lastData.curveRoadPoints[key];
    }

    for (const key in this.lastData.curveRoadPoints) {
      const item = {
        handle: HistoryEvents.DeleteCurveRoadPoint,
        curveRoadPoint: historyUtil.getDataForCurveRoadPoint(
          this.lastData.curveRoadPoints[key]
        ),
      };
      this.currentData.curveRoadPoints.push(item);
    }
  }

  compareCurveRoads() {
    this.currentData.curveRoads = [];
    const curveRoads = dataService.getCurveRoads();

    for (const key in curveRoads) {
      const curveRoad = curveRoads[key];
      const lastCurveRoad = this.lastData.curveRoads[key];

      // 不存在意味着增加
      if (!lastCurveRoad) {
        const item = {
          handle: HistoryEvents.AddCurveRoad,
          curveRoad: historyUtil.getDataForCurveRoad(curveRoad),
        };
        this.currentData.curveRoads.push(item);
      } else {
        if (!historyUtil.isDifferentForCurveRoads(curveRoad, lastCurveRoad)) {
          delete this.lastData.curveRoads[key];
          continue;
        } else {
          const item = {
            handle: HistoryEvents.ModifyCurveRoad,
            preCurveRoad: historyUtil.getDataForCurveRoad(lastCurveRoad),
            curCurveRoad: historyUtil.getDataForCurveRoad(curveRoad),
          };
          this.currentData.curveRoads.push(item);
        }
      }
      delete this.lastData.curveRoads[key];
    }

    for (const key in this.lastData.curveRoads) {
      const item = {
        handle: HistoryEvents.DeleteCurveRoad,
        curveRoad: historyUtil.getDataForCurveRoad(
          this.lastData.curveRoads[key]
        ),
      };
      this.currentData.curveRoads.push(item);
    }
  }

  compareCurveRoadEdges() {
    this.currentData.curveRoadEdges = [];
    const curveRoadEdges = dataService.getCurveRoadEdges();

    for (const key in curveRoadEdges) {
      const curveRoadEdge = curveRoadEdges[key];
      const lastCurveRoadEdge = this.lastData.curveRoadEdges[key];

      // 不存在意味着增加
      if (!lastCurveRoadEdge) {
        const item = {
          handle: HistoryEvents.AddCurveRoadEdge,
          curveRoadEdge: historyUtil.getDataForCurveRoadEdge(curveRoadEdge),
        };
        this.currentData.curveRoadEdges.push(item);
      } else {
        if (
          !historyUtil.isDifferentForCurveRoadEdges(
            curveRoadEdge,
            lastCurveRoadEdge
          )
        ) {
          delete this.lastData.curveRoadEdges[key];
          continue;
        } else {
          const item = {
            handle: HistoryEvents.ModifyCurveRoadEdge,
            preCurveRoadEdge:
              historyUtil.getDataForCurveRoadEdge(lastCurveRoadEdge),
            curCurveRoadEdge:
              historyUtil.getDataForCurveRoadEdge(curveRoadEdge),
          };
          this.currentData.curveRoadEdges.push(item);
        }
      }
      delete this.lastData.curveRoadEdges[key];
    }

    for (const key in this.lastData.curveRoadEdges) {
      const item = {
        handle: HistoryEvents.DeleteCurveRoadEdge,
        curveRoadEdge: historyUtil.getDataForCurveRoadEdge(
          this.lastData.curveRoadEdges[key]
        ),
      };
      this.currentData.curveRoadEdges.push(item);
    }
  }

  compareCrossPoints() {
    this.currentData.crossPoints = [];
    const crossPoints = dataService.getCrossPoints();

    for (const key in crossPoints) {
      const crossPoint = crossPoints[key];
      const lastCrossPoint = this.lastData.crossPoints[key];

      // 不存在意味着增加
      if (!lastCrossPoint) {
        const item = {
          handle: HistoryEvents.AddCrossPoint,
          crossPoint: historyUtil.getDataForCrossPoint(crossPoint),
        };
        this.currentData.crossPoints.push(item);
      } else {
        if (
          !historyUtil.isDifferentForCrossPoints(crossPoint, lastCrossPoint)
        ) {
          delete this.lastData.crossPoints[key];
          continue;
        } else {
          const item = {
            handle: HistoryEvents.ModifyCrossPoint,
            preCrossPoint: historyUtil.getDataForCrossPoint(lastCrossPoint),
            curCrossPoint: historyUtil.getDataForCrossPoint(crossPoint),
          };
          this.currentData.crossPoints.push(item);
        }
      }
      delete this.lastData.crossPoints[key];
    }

    for (const key in this.lastData.crossPoints) {
      const item = {
        handle: HistoryEvents.DeleteCrossPoint,
        crossPoint: historyUtil.getDataForCrossPoint(
          this.lastData.crossPoints[key]
        ),
      };
      this.currentData.crossPoints.push(item);
    }
  }

  compareSettings() {
    const lastSettings = this.lastData.settings;
    this.currentData.settings = null;
    if (historyUtil.isDifferentForSettings(Settings, lastSettings)) {
      const item = {
        handle: HistoryEvents.ModifySettings,
        preSettings: historyUtil.getDataForSettings(lastSettings),
        curSettings: historyUtil.getDataForSettings(Settings),
      };
      this.currentData.settings = item;
    }
  }
}

const change = new Change();
export { change };