TypeScript function to return nullable Promise
Question
I'm trying to create a function that returns a Promise with values that can be resolved to null.
Basically something like this:
static getUserById(ids: String): Promise<?User> {
// do something
}
but it is returning an error
Generic type 'Promise' requires 1 type argument(s)
How to create a function in TypeScript that can return a Promise with nullable resolved values?
1 answers
solution1
52 ACCPTED 2017-07-10 10:00:42
? means optionnal parameter not nullable type .
You should use this:
Promise<User|null>
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.
Related Question
Async TypeScript function return jQuery promise
Typescript does not allow an extended class promise to be the return type of an async function
TypeScript function gives did not return a value, a promise, or throw an error
In TypeScript, what is the best way to define a function that can return either Promise<T> or Promise<T[]>?
typescript promise return after loop
Return promise from the function
return function value with promise
declare promise type in typescript of a function
Typescript async function wrapping promise
How to return boolean from async await function instead of Promise<boolean> (Typescript | React)
Related Tags