Why I get this warning in TS ?
Type 'unknown' is not assignable to type 'PokemonList'.ts(2322)
This error is on line: "return e"
Code:
export interface PokemonList {
count: number;
next: string;
previous?: any;
results: {
name: string;
url: string;
}[]
};
const PokeApi = async (): Promise<PokemonList> => {
try {
const res = await fetch('https://pokeapi.co/api/v2/pokemon?limit=10');
return res.json()
} catch(e) {
return e;
}
};
If I make this:
( Promise<PokemonList> | unknown )
then I get this error:
The return type of an async function or method must be the global Promise<T> type. Did you mean to write 'Promise<unknown>'?ts(
The return type of that function is
Promise<PokemonList | Error>
As Keith said, this is "Not a good idea, doing this you have now broken your promise chain.". Promises have .catch and work in try/catch to chain Promises together. What you have you require an if(/else) check, which is not what Promises are meant for.
To fix this, you should remove the try/catch block inside the function and just handle errors with catch whenever you call it.
const PokeApi = async (): Promise<PokemonList> => {
const res = await fetch('https://pokeapi.co/api/v2/pokemon?limit=10');
return res.json()
};
// when calling it inside async function
let pokemonList: PokemonList;
try {
pokemonList = await PokeApi();
} catch (e) {
// Handle error
}