kitchen-simulator/es/reducers/vertices-reducer.js

It is a kitchen simulator (self-contained micro-frontend).

import { BEGIN_DRAGGING_VERTEX, UPDATE_DRAGGING_VERTEX, END_DRAGGING_VERTEX } from "../constants";
import { history } from "../utils/export";
import { Vertex } from "../class/export";
export default function (state, action) {
  switch (action.type) {
    case BEGIN_DRAGGING_VERTEX:
      return Vertex.beginDraggingVertex(state, action.layerID, action.vertexID, action.x, action.y).updatedState;
    case UPDATE_DRAGGING_VERTEX:
      return Vertex.updateDraggingVertex(state, action.x, action.y).updatedState;
    case END_DRAGGING_VERTEX:
      // Code that saving the scene history (26 ~ 28)
      state = state.merge({
        sceneHistory: history.historyPush(state.sceneHistory, state.scene)
      });
      return Vertex.endDraggingVertex(state, action.x, action.y).updatedState;
    default:
      return state;
  }
}