namae/api/services/appstore/[query].ts

import {send, sendError, fetch} from '../../../util/http';
import {NowRequest, NowResponse} from '@vercel/node';

interface App {
  trackId: string;
  trackName: string;
  kind: string;
  version: string;
  price: string;
  trackViewUrl: string;
}

interface AppStoreResponse {
  results: App[];
}

export default async function handler(
  req: NowRequest,
  res: NowResponse,
): Promise<void> {
  const {query, country} = req.query;

  if (!query || typeof query !== 'string') {
    return sendError(res, new Error('No query given'));
  }

  const term = encodeURIComponent(query);
  const countryCode = country || 'us';
  const limit = 10;

  try {
    const response = await fetch(
      `https://itunes.apple.com/search?media=software&entity=software,iPadSoftware,macSoftware&country=${countryCode}&limit=${limit}&term=${term}`,
      'GET',
    );
    const body: AppStoreResponse = await response.json();
    const apps = body.results.map((app) => ({
      id: app.trackId,
      name: app.trackName,
      kind: app.kind,
      version: app.version,
      price: app.price,
      viewURL: app.trackViewUrl,
    }));
    send(res, {result: apps || []});
  } catch (err) {
    sendError(res, err);
  }
}