How to fix No overload matches TS error?

Question

typescript

There is something like this code:

// реализация
function providerGetItem(id: number): Item
function providerGetItem(id: number[]): Item[]
function providerGetItem(id: number | number[]): Item | Item[] {
    return typeof id === 'number' ? {id} : id.map(id => ({id}))
}


// Абстракция
function getItem(id: number): Item
function getItem(id: number[]): Item[]
function getItem(id: number | number[]): Item | Item[] {
    return providerGetItem(id) // <-- TS2769: No overload matches this call
}

Playground .

The call providerGetItem(id)results in an error:

TS2769: No overload matches this call.   
Overload 1 of 2, '(myAnimeListId: number): Promise<Series | undefined>', gave the following error.     
Argument of type 'number | number[]' is not assignable to parameter of type 'number'.       
Type 'number[]' is not assignable to type 'number'.   

Overload 2 of 2, '(myAnimeListId: number[]): Promise<Series[]>', gave the following error.     
Argument of type 'number | number[]' is not assignable to parameter of type 'number[]'.       
Type 'number' is not assignable to type 'number[]'.

How to fix it? The only thing that came to mind:

typeof id === 'number' ? providerGetItem(id) : providerGetItem(id)

Answer 1

In your code - in the implementation, you set a vinaigrette of types - and of the same name - and the compiler gets confused - which one to use - remove the extra ones - and leave the general one (where you can pass either a number or an array with a number) - and everything will work.
Or there is another option like what you suggested - they will check the input type of the argument - that is, on if-s - if a number - then one return, if the array is different (set the same for testing) - everything works - only more code.
type Item = {id: number}
function providerGetItem(id: number | number[]): Item | Item[] {
return typeof id === 'number' ? {id} : id.map(id => ({id}))
}
function getItem(id: number | number[]): Item | Item[] {
return providerGetItem(id);
}
console.log(getItem(1))
console.log(getItem([2]))