option-t/esm/undefinable/zip_with_async.js

A toolkit of Nullable/Option/Result type implementation in ECMAScript. Their APIs are inspired by Rust's `Option<T>` and `Result<T, E>`.

import { ERR_MSG_TRANSFORMER_MUST_NOT_RETURN_NO_VAL_FOR_UNDEFINABLE } from './internal/error_message.js';
import { expectNotUndefined, isUndefined, } from './undefinable.js';
/**
 *  Zips _self_ and another `Undefinable` with function _transformer_.
 *  If _self_ is `T` and _other_ is `U`, this method returns the result of _transformer_.
 *  Otherwise, `undefined` is returned.
 *
 *  @throws {TypeError}
 *      Throws if the _transformer_ returns `undefined`.
 */
export async function zipWithAsyncForUndefinable(self, other, transformer) {
    if (isUndefined(self) || isUndefined(other)) {
        return undefined;
    }
    const result = await transformer(self, other);
    const checked = expectNotUndefined(result, ERR_MSG_TRANSFORMER_MUST_NOT_RETURN_NO_VAL_FOR_UNDEFINABLE);
    return checked;
}