Typescript Contentful type

types.ts

import { createClient, EntryCollection, ContentTypeLink, Entry, Sys } from 'contentful';

type FlatEntry<T> = {
  id: Sys['id'];
  contentType: ContentTypeLink['id'];
} & T;

type ValueOf<T> = T[keyof T];

function flatten<T>(contentfulValue: Entry<T> | ValueOf<T>) {
  if (Array.isArray(contentfulValue)) {
    return contentfulValue.map(item => flatten(item));
  }

  const entry = contentfulValue as Entry<T>;
  if (entry?.fields) {
    return flattenEntry(entry);
  }

  return contentfulValue;
}

function flattenEntryCollection<T>(entryCollection: EntryCollection<T>): FlatEntry<T>[] {
  return entryCollection.items.map(item => flattenEntry(item));
}

function flattenEntry<T>(entry: Entry<T>): FlatEntry<T> {
  return {
    id: entry.sys.id,
    contentType: entry.sys.contentType.sys.id,
    // ...Object.entries(entry.fields).reduce(
    //   (acc, [key, value]) => ({
    //     ...acc,
    //     [key]: Array.isArray(value) ? value.map()
    //   }),
    ...Object.keys(entry.fields).reduce((acc, key) => {
      return Object.assign(acc, { [key]: flatten(entry.fields[key]) });
    }, {} as T) as T
  };
}

const client = createClient({
  space: 'utaji99zkvj6',
  accessToken: 'c9e06be482d24784f886738260047ac9c19536dd84e5fb82b52c70b4747b798a',
  host: 'contentful.aceandtate.show'
});

//  TODO: add static list of country strings
type Country = string;

type Query = {
  country?: Country;
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  [key: string]: any;
}

function queryCountry(country?: Country) {
  if (typeof country !== 'string') {
    return {};
  }
  return {
    'fields.countryConfiguration.sys.contentType.sys.id': 'CountryConfiguration',
    'fields.countryConfiguration.fields.includeInCountries': country.toLowerCase()
  };
}

export async function getEntries<T>(query: Query) {
  const { country, ...rest } = query;
  const result = await client.getEntries<T>({
    ...rest,
    ...queryCountry(country)
  });
  return flattenEntryCollection(result);
}

export async function getEntry<T>(query: Query) {
  const result = await getEntries(query);
  return result[0];
}