Class IsolateModule

dom/src/IsolateModule.ts:5–136

const MapPolyfill: typeof Map = require('es6-map');

export class IsolateModule {
  private elementsByFullScope: Map<string, Element>;

  /**
   * A Map where keys are full scope strings and values are many delegators
   * for that scope. The only reason why this data structure is here is to
   * be able to update the origin element inside those delegators.
   * The delegators are never created in this class.
   */
  private delegatorsByFullScope: Map<string, Array<EventDelegator>>;

  /**
   * A registry of full scopes representing scopes that are currently
   * being updated in delegators or elements. This is useful to avoid
   * cleaning up data structures for an element that is being *replaced*,
   * not *removed* in the virtual DOM.
   */
  private fullScopesBeingUpdated: Array<string>;

  constructor() {
    this.elementsByFullScope = new MapPolyfill<string, Element>();
    this.delegatorsByFullScope = new MapPolyfill<string, Array<EventDelegator>>();
    this.fullScopesBeingUpdated = [];
  }

  private cleanupVNode({data, elm}: VNode) {
    const fullScope: string = (data || {} as any).isolate || '';
    const isCurrentElm = this.elementsByFullScope.get(fullScope) === elm;
    const isScopeBeingUpdated = this.fullScopesBeingUpdated.indexOf(fullScope) >= 0;
    if (fullScope && isCurrentElm && !isScopeBeingUpdated) {
      this.elementsByFullScope.delete(fullScope);
      this.delegatorsByFullScope.delete(fullScope);
    }
  }

  public getElement(fullScope: string): Element | undefined {
    return this.elementsByFullScope.get(fullScope);
  }

  public getFullScope(elm: Element): string {
    const iterator = this.elementsByFullScope.entries();
    for (let result = iterator.next(); !!result.value; result = iterator.next()) {
      const [fullScope, element] = result.value;
      if (elm === element) {
        return fullScope;
      }
    }
    return '';
  }

  public addEventDelegator(fullScope: string, eventDelegator: EventDelegator) {
    let delegators = this.delegatorsByFullScope.get(fullScope);
    if (!delegators) {
      delegators = [];
      this.delegatorsByFullScope.set(fullScope, delegators);
    }
    delegators[delegators.length] = eventDelegator;
  }