HostVsStoresRouter class Bug 1542035

HostVsStoresRouter.js

// in storage actor's `populateStoresForHost` method...
this.hostVsStores = new HostVsStoresRouter(host);

// Add an intermediary "area" layer between host and storeMap in this.hostVsStores
class HostVsStoresRouter {
  constructor(host) {
    this.DEFAULT_AREA = "local";
    // a triple nested map: host => areaMap, where areaMap is area => storeMap and storeMap is key => value
    this.router = (new Map()),set(host, new Map());
  },
  
  get(host, area = this.DEFAULT_AREA) {
    return this.router.get(host).get(area);
  },
  
  set(host, storeMap, area = this.DEFAULT_AREA) {
    this.router.get(host).set(area, storeMap);
  },
  
  // Needed for getValuesForHost, which should return an array of `item` objects of the form {name, value, area}
  getAllItems(host) {
    const items = [];
    for (const areaMap of this.router.get(host)) {
      for (const [area, storeMap] of Object.entries(areaMap)) {
        for (const [name, value] of Object.entries(storeMap)) {
          const item = {name, value, area};
          items.push(item);
        }
      }
    }
    return items;
  },
}