hexbear-frontend/src/linkEvent.ts

// mimic the linkEvent function from inferno for easier migration

// helpers from inferno-shared
// https://github.com/infernojs/inferno/blob/master/packages/inferno-shared/src/index.ts
// @ts-ignore
// eslint-disable-next-line @typescript-eslint/ban-types
export function isFunction(o: any): o is Function {
  return typeof o === 'function';
}

export function isNull(o: any): o is null {
  return o === null;
}

export interface LinkedEvent<T, E extends Event> {
  data: T;
  event: (data: T, event: E) => void;
}

/**
 * Links given data to event as first parameter
 * @param {*} data data to be linked, it will be available in function as first parameter
 * @param {Function} event Function to be called when event occurs
 * @returns {{data: *, event: Function}}
 */
export function linkEvent<T, E extends Event>(
  data: T,
  event: (data: T, event: E) => void
  // @TODO: Properly type this at some point, but i have no idea how to do it with curried functions like this
): any {
  if (isFunction(event)) {
    return evt => event(data, evt);
  }
  return null; // Return null when event is invalid, to avoid creating unnecessary event handlers
}

// object.event should always be function, otherwise its badly created object.
export function isLinkEventObject(o): o is LinkedEvent<any, any> {
  return !isNull(o) && typeof o === 'object';
}