If you are curious how components' state is handled, they employed the React class components method:

  // Import the StatefulComponent
  import { StatefulComponent } from 'valdi_core/src/Component';
  
  // ViewModel + State interfaces for component
  export interface TimerViewModel { loop: number }
  interface TimerState { elapsed: number }
  
  // Component class
  export class Timer extends StatefulComponent<TimerViewModel, TimerState> {
    // Initialize the state
    state = { elapsed: 0 };
    // When creating the component, start a periodic logic
    private interval?: number;
  
    // Initialize the setInterval that will update state once a second incrementing
    // the `elapsed` state value.
    onCreate() {
      this.interval = setInterval(() => {
        // Increment the state to trigger a re-render periodically
        const elapsed = this.state.elapsed;
        const loop = this.viewModel.loop;
        this.setState({ elapsed: (elapsed + 1) % loop });
      }, 1000);
    }
  
    // When component is removed, make sure to cleanup interval logic
    onDestroy() {
      if (this.interval) clearInterval(this.interval);
    }
  
    // Render visuals will depend both on the state and the view model
    onRender() {
      <view padding={30} backgroundColor='lightblue'>
        <label value={`Time Elapsed: ${this.state.elapsed} seconds`} />;
        <label value={`Time Looping every: ${this.viewModel.loop} seconds`} />;
      </view>;
    }
  }

https://github.com/Snapchat/Valdi/blob/main/docs/docs/core-s...