_hookUpViewport()

in js/index.js [104:132]

• 17 lines of code
• 4 McCabe index (conditional complexity)

  _hookUpViewport() {
    this.viewport = this._initViewport();

    if (this.virtualized) {
      let blockUntil = 0;

      const onViewportChange = () => {
        if (performance.now() > blockUntil) {
          this._scheduleRedraw();
        } else if (!this._state.removed) {
          // If the scroll events are blocked, we shouldn't just swallow them.
          // Wait for 0.1 second and give another try.
          window.setTimeout(onViewportChange, 100);
        }
      };

      this.viewport.on('change', onViewportChange);

      //
      // On keypress, we want to block the scroll events for 0.2 second to wait
      // for the animation to complete. Otherwise, the scroll would change the
      // geometry metrics and break the animation. The worst thing we may get is,
      // for 'HOME' and 'END' keys, the view doesn't scroll to the right position.
      //
      this.viewport.on('keypress', () => {
        blockUntil = performance.now() + 200;
      });
    }
  }