option-t
Version:
A toolkit of Nullable/Option/Result type implementation in ECMAScript. Their APIs are inspired by Rust's `Option<T>` and `Result<T, E>`.
28 lines (27 loc) • 1.32 kB
JavaScript
import { isNotUndefined, expectNotUndefined, } from '../core/undefinable.js';
import { ERR_MSG_TRANSFORMER_MUST_NOT_RETURN_NO_VAL_FOR_UNDEFINABLE, ERR_MSG_RECOVERER_MUST_NOT_RETURN_NO_VAL_FOR_UNDEFINABLE, } from '../internal/error_message.js';
/**
* Return the result of _transformer_ with using _input_ as an argument for it if _input_ is not `undefined`.
* Otherwise, return the result of _recoverer_.
*
* Basically, this operation is a combination `map()` and `unwrapOrElse()`.
*
* * `U` must not be `Undefinable<*>`.
* * If the result of _transformer_ is `undefined`, this throw an `Error`.
* * If the result of _recoverer_ is undefined`, this throw an `Error`.
* * If you'd like to accept `Undefinable<*>` as `U`, use a combination `andThen()` and `orElse()`.
*/
export async function mapOrElseAsyncForUndefinable(input, recoverer, transformer) {
let result;
let messageForExpect = '';
if (isNotUndefined(input)) {
result = await transformer(input);
messageForExpect = ERR_MSG_TRANSFORMER_MUST_NOT_RETURN_NO_VAL_FOR_UNDEFINABLE;
}
else {
result = await recoverer();
messageForExpect = ERR_MSG_RECOVERER_MUST_NOT_RETURN_NO_VAL_FOR_UNDEFINABLE;
}
const checked = expectNotUndefined(result, messageForExpect);
return checked;
}