mobx#isComputedProp TypeScript Examples

/**
   * Call `get hashCode()` on each element once so we trigger the first time we compute the hash for that element.
   * Notice that we do this in asynchronous manner to not block the main execution thread, as this is quiet an expensive
   * task.
   *
   * We also want to take advantage of `mobx computed` here so we save time when starting change detection. However,
   * since `mobx computed` does not track async contexts, we have to use the `keepAlive` option for `computed`
   *
   * To avoid memory leak potentially caused by `keepAlive`, we use `keepAlive` utility from `mobx-utils`
   * so we could manually dispose `keepAlive` later after we already done with starting change detection.
   */
  async preComputeGraphElementHashes(): Promise<void> {
    const startTime = Date.now();
    const disposers: IDisposer[] = [];
    if (this.editorStore.graphManagerState.graph.allOwnElements.length) {
      await Promise.all<void>(
        this.editorStore.graphManagerState.graph.allOwnElements.map((element) =>
          promisify(() => {
            if (isComputedProp(element, 'hashCode')) {
              disposers.push(keepAlive(element, 'hashCode'));
            }
            // manually trigger hash code computation
            element.hashCode;
          }),
        ),
      );
    }
    // save the `keepAlive` computation disposers to dispose after we start change detection
    // so the first call of change detection still get the benefit of computed value
    this.graphElementHashCodeKeepAliveComputationDisposers = disposers;
    this.editorStore.applicationStore.log.info(
      LogEvent.create(
        CHANGE_DETECTION_EVENT.CHANGE_DETECTION_GRAPH_HASHES_PRECOMPUTED,
      ),
      '[ASYNC]',
      Date.now() - startTime,
      'ms',
    );
  }