option-t/esm/plain_result/operators/is_err_and.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 { isOk } from '../core/result.js';
import { unsafeUnwrapValueInErrWithoutAnyCheck } from '../internal/intrinsics_unsafe.js';
/**
 *  Returns `true` if the _result_ is `Err<E>` and the value inside of it matches a _predicate_.
 */
// XXX:
// We cannot use `result is Err<E>` as the returned type here because of that
// it **does not mean** "result is not Err<E>" even if _predicate_ returns `false`.
export function isErrAndForResult(result, predicate) {
    if (isOk(result)) {
        return false;
    }
    const err = unsafeUnwrapValueInErrWithoutAnyCheck(result);
    const ok = predicate(err);
    return ok;
}
/**
 *  Returns `true` if the _result_ is `Ok<T>` and the value inside of it matches a _predicate_.
 *  Then _result_ would be `Err<F>`.
 *
 *  Please use {@link isErrAndForResult} generally if you don't have to narrow the type.
 */
export function isErrAndWithEnsureTypeForResult(result, predicate) {
    const ok = isErrAndForResult(result, predicate);
    return ok;
}