option-t/esm/plain_result/operators/map_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 { createOk, isErr } from '../core/result.js';
import { unsafeUnwrapValueInOkWithoutAnyCheck } from '../internal/intrinsics_unsafe.js';
/**
 *  Maps a `Result<T, E>` to `Result<U, E>` by applying a _transformer_ function
 *  to an contained `Ok(T)` value, leaving an `Err(E)` value untouched.
 *
 *  This function can be used to compose the results of two functions.
 */
export async function mapAsyncForResult(input, transformer) {
    if (isErr(input)) {
        const fallback = input;
        return fallback;
    }
    const inner = unsafeUnwrapValueInOkWithoutAnyCheck(input);
    const mapped = await transformer(inner);
    const result = createOk(mapped);
    return result;
}