typescript-practice/conditionals.ts at main · danilamdev/typescript-practice · GitHub

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import fetch from 'node-fetch';


interface PokemonResults {
  count: number
  next?: string
  previous?: string
  results: {
    name: string
    url: string
  }[]
}

type fetchPokemonResult<T> = T extends undefined
  ? Promise<PokemonResults>
  : void

function fetchPokemon<T extends undefined | ((data: PokemonResults) => void)>(url: string, cb?: T)
  : fetchPokemonResult<T> {
  if (cb) {
    fetch(url)
      .then(res => res.json())
      .then(cb)
    return undefined as fetchPokemonResult<T>
  } else {
    return fetch(url).then(res => res.json()) as fetchPokemonResult<T>
  }
}

// fetchPokemon('https://pokeapi.co/api/v2/pokemon?limit=10', (data) => {
//   data.results.forEach(pokemon => console.log(pokemon.name))
// })

(async function () {
  const data = <PokemonResults>(await fetchPokemon('https://pokeapi.co/api/v2/pokemon?limit=10'))
  data.results.forEach(pokemon => console.log(pokemon.name))
})()