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diff --git a/node_modules/rxjs/src/internal/scheduler/VirtualTimeScheduler.ts b/node_modules/rxjs/src/internal/scheduler/VirtualTimeScheduler.ts
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+++ b/node_modules/rxjs/src/internal/scheduler/VirtualTimeScheduler.ts
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+import { AsyncAction } from './AsyncAction';
+import { Subscription } from '../Subscription';
+import { AsyncScheduler } from './AsyncScheduler';
+import { SchedulerAction } from '../types';
+import { TimerHandle } from './timerHandle';
+
+export class VirtualTimeScheduler extends AsyncScheduler {
+  /** @deprecated Not used in VirtualTimeScheduler directly. Will be removed in v8. */
+  static frameTimeFactor = 10;
+
+  /**
+   * The current frame for the state of the virtual scheduler instance. The difference
+   * between two "frames" is synonymous with the passage of "virtual time units". So if
+   * you record `scheduler.frame` to be `1`, then later, observe `scheduler.frame` to be at `11`,
+   * that means `10` virtual time units have passed.
+   */
+  public frame: number = 0;
+
+  /**
+   * Used internally to examine the current virtual action index being processed.
+   * @deprecated Internal implementation detail, do not use directly. Will be made internal in v8.
+   */
+  public index: number = -1;
+
+  /**
+   * This creates an instance of a `VirtualTimeScheduler`. Experts only. The signature of
+   * this constructor is likely to change in the long run.
+   *
+   * @param schedulerActionCtor The type of Action to initialize when initializing actions during scheduling.
+   * @param maxFrames The maximum number of frames to process before stopping. Used to prevent endless flush cycles.
+   */
+  constructor(schedulerActionCtor: typeof AsyncAction = VirtualAction as any, public maxFrames: number = Infinity) {
+    super(schedulerActionCtor, () => this.frame);
+  }
+
+  /**
+   * Prompt the Scheduler to execute all of its queued actions, therefore
+   * clearing its queue.
+   */
+  public flush(): void {
+    const { actions, maxFrames } = this;
+    let error: any;
+    let action: AsyncAction<any> | undefined;
+
+    while ((action = actions[0]) && action.delay <= maxFrames) {
+      actions.shift();
+      this.frame = action.delay;
+
+      if ((error = action.execute(action.state, action.delay))) {
+        break;
+      }
+    }
+
+    if (error) {
+      while ((action = actions.shift())) {
+        action.unsubscribe();
+      }
+      throw error;
+    }
+  }
+}
+
+export class VirtualAction<T> extends AsyncAction<T> {
+  protected active: boolean = true;
+
+  constructor(
+    protected scheduler: VirtualTimeScheduler,
+    protected work: (this: SchedulerAction<T>, state?: T) => void,
+    protected index: number = (scheduler.index += 1)
+  ) {
+    super(scheduler, work);
+    this.index = scheduler.index = index;
+  }
+
+  public schedule(state?: T, delay: number = 0): Subscription {
+    if (Number.isFinite(delay)) {
+      if (!this.id) {
+        return super.schedule(state, delay);
+      }
+      this.active = false;
+      // If an action is rescheduled, we save allocations by mutating its state,
+      // pushing it to the end of the scheduler queue, and recycling the action.
+      // But since the VirtualTimeScheduler is used for testing, VirtualActions
+      // must be immutable so they can be inspected later.
+      const action = new VirtualAction(this.scheduler, this.work);
+      this.add(action);
+      return action.schedule(state, delay);
+    } else {
+      // If someone schedules something with Infinity, it'll never happen. So we
+      // don't even schedule it.
+      return Subscription.EMPTY;
+    }
+  }
+
+  protected requestAsyncId(scheduler: VirtualTimeScheduler, id?: any, delay: number = 0): TimerHandle {
+    this.delay = scheduler.frame + delay;
+    const { actions } = scheduler;
+    actions.push(this);
+    (actions as Array<VirtualAction<T>>).sort(VirtualAction.sortActions);
+    return 1;
+  }
+
+  protected recycleAsyncId(scheduler: VirtualTimeScheduler, id?: any, delay: number = 0): TimerHandle | undefined {
+    return undefined;
+  }
+
+  protected _execute(state: T, delay: number): any {
+    if (this.active === true) {
+      return super._execute(state, delay);
+    }
+  }
+
+  private static sortActions<T>(a: VirtualAction<T>, b: VirtualAction<T>) {
+    if (a.delay === b.delay) {
+      if (a.index === b.index) {
+        return 0;
+      } else if (a.index > b.index) {
+        return 1;
+      } else {
+        return -1;
+      }
+    } else if (a.delay > b.delay) {
+      return 1;
+    } else {
+      return -1;
+    }
+  }
+}