option-t/esm/undefinable/operators/transpose.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 { createOk, isOk } from '../../plain_result/core/result.js';
import { isUndefined } from '../core/undefinable.js';
/**
 *  Transposes a `Undefinable` of a `Result` into an `Result` of a `Undefinable`.
 *
 *  - `undefined` -> `Ok<undefined>`.
 *  - `Ok<T>` -> `Ok<T>`.
 *  - `Err<E>` -> `Err<E>`.
 */
export function transposeUndefinableToResult(input) {
    if (isUndefined(input)) {
        return createOk(undefined);
    }
    if (isOk(input)) {
        const rv = input;
        return rv;
    }
    const rv = input;
    return rv;
}