Typescript

Create adsgram.d.ts file and add it to types folder or existing folder with types declarations.

adsgram.d.ts

export interface ShowPromiseResult {
  done: boolean;
  description: string;
  state: 'load' | 'render' | 'playing' | 'destroy';
  error: boolean;
}

type BannerType = 'RewardedVideo' | 'FullscreenMedia';

interface AdsgramInitParams {
  blockId: string;
  debug?: boolean;
  debugBannerType?: BannerType;
}

type EventType = 'onReward' | 'onStart' | 'onSkip' | 'onBannerNotFound' | 'onError';
type HandlerType = () => void;

export interface AdController {
  show(): Promise<ShowPromiseResult>;
  addEventListener(event: EventType, handler: HandlerType): void;
  removeEventListener(event: EventType, handler: HandlerType): void;
  destroy(): void;
}

declare global {
    interface Window {
      Adsgram?: {
        init(params: AdsgramInitParams): AdController;
      };
    }
}

P.s. package with types will be in the future.