Asynchronous operation state modeled as NotStarted, Loading, Success, Error with functional-style extensions, Either interop and testing helpers for concise, explicit handling of load/error flows.
AsyncResult is a small Kotlin Multiplatform library to model asynchronous operations using a sealed hierarchy. It captures the common states you deal with in UI and data layers:
NotStarted - The operation hasn't begun yetLoading - The operation is in progressSuccess - The operation completed successfully with a valueError - The operation failed, optionally with a throwable, metadata, and error IDThe library provides a rich set of operators for transforming, combining, and extracting values from these states, making it easy to handle async operations in a type-safe way.
The core module contains the type hierarchy and all essential utilities:
Extensions for interoperability with Arrow's Either type:
Testing utilities built on assertk:
dependencies {
implementation("io.nlopez.asyncresult:asyncresult:<version>")
// Optional: Arrow Either interop
implementation("io.nlopez.asyncresult:asyncresult-either:<version>")
// Optional: Testing helpers
testImplementation("io.nlopez.asyncresult:asyncresult-test:<version>")
}
📚 mrmans0n.github.io/asyncresult
mapSuccess, mapError, flatMap, flatten, bimap, fold, orError, filterOrError, castOrErrorisSuccess, isError, isIncomplete, isSuccessAnd, isErrorAnd, isErrorWithMetadataAnd, containsgetOrNull, getOrDefault, getOrElse, getOrThrow, getOrEmpty, errorOrNull, errorWithMetadataOrNull, throwableOrNull, errorIdOrNullonSuccess, onLoading, onError, onErrorWithMetadata, onNotStarted, onIncompleteunwrap, unwrapError, unwrapThrowable, unwrapMetadata, unwrapErrorId, expect, expectError, expectThrowable, expectMetadata, expectErrorId (Rust-style extraction)zip, zipWith, and, andThen, spread, combine, sequencerecover, recoverIf, or, orElsetoErrorIf, toErrorUnlessresult { } comprehension with bind(), error(), loading(), ensure(), ensureNotNull()asAsyncResult, onLoading, onSuccess, onError, onIncomplete, skipWhileLoading, filterNotLoading, cacheLatestSuccess, timeoutToError, retryOnError, retryOnErrorWithMetadataerrors, successes, throwables, incompletes, metadata, anyLoading, anyIncomplete, anyError, errorsFrom, partitiontoAsyncResult() to convert Either to AsyncResultbind() to flatten AsyncResult<Either<L, R>> to AsyncResult<R>asAsyncResult() to convert Flow<Either<L, R>> to Flow<AsyncResult<R>>, toEither() to convert Flow<AsyncResult<T>> to EitherRaise<Error>.bind() to use AsyncResult inside Arrow's either { } / result { } blocksisNotStarted(), isLoading(), isIncomplete(), isSuccess(), isError()isSuccessEqualTo(), isErrorWithMetadata(), isErrorWithMetadataEqualTo()isErrorWithThrowable(), isErrorWithThrowableOfType(), isErrorWithThrowableMessage(), isErrorWithId(), isErrorWithIdEqualTo(), hasErrorId()assertSuccess(), assertError(), assertErrorWithMetadata(), assertErrorWithId(), assertFirstIsLoading(), assertFirstIsNotStarted(), assertFirstIsIncomplete()hasAnyLoading(), hasAnyIncomplete(), allErrors(), allErrorMetadata()MIT License
Copyright (c) 2026 Nacho Lopez
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