Method onStateChange

codebase/sources/dhtmlxscheduler.js:9017–9025

(handler)

      }
    }
    onStateChange(handler) {
      this.onStateChangeHandlers.push(handler);
      return () => {
        const index = this.onStateChangeHandlers.indexOf(handler);
        if (index !== -1) {
          this.onStateChangeHandlers.splice(index, 1);
        }
      };
    }
    _notifyStateChange(oldState, newState) {
      this.onStateChangeHandlers.forEach((handler) => handler(oldState, newState));
    }