@temporal-contract/boxed

---

@temporal-contract/boxed

Custom implementation of Future and Result patterns for Temporal workflows

This package provides a Temporal-compatible implementation of the Result and Future patterns that were originally provided by @swan-io/boxed.

Classes

Err

Defined in: result.ts:70

Err variant representing a failed result.

Named Err to avoid shadowing the global Error constructor. Use Result.Error() factory or isError() type guard in consuming code.

Type Parameters

Type Parameter
T
E

Constructors

Constructor

new Err<T, E>(error): Err<T, E>;

Defined in: result.ts:74

Parameters

Parameter	Type
error	E

Returns

Err<T, E>

Properties

Property	Modifier	Type	Defined in
error	readonly	E	result.ts:72
tag	readonly	"Error"	result.ts:71

Methods

flatMap()

flatMap<U>(_fn): Result<U, E>;

Defined in: result.ts:94

Type Parameters

Type Parameter
U

Parameters

Parameter	Type
_fn	(value) => Result<U, E>

Returns

Result<U, E>

flatMapOk()

flatMapOk<U>(_fn): Result<U, E>;

Defined in: result.ts:98

Type Parameters

Type Parameter
U

Parameters

Parameter	Type
_fn	(value) => Result<U, E>

Returns

Result<U, E>

getOr()

getOr(defaultValue): T;

Defined in: result.ts:102

Parameters

Parameter	Type
defaultValue	T

Returns

T

getWithDefault()

getWithDefault(defaultValue): T;

Defined in: result.ts:106

Parameters

Parameter	Type
defaultValue	T

Returns

T

isError()

isError(): this is Err<T, E>;

Defined in: result.ts:82

Returns

this is Err<T, E>

isOk()

isOk(): this is Ok<T, E>;

Defined in: result.ts:78

Returns

this is Ok<T, E>

map()

map<U>(_fn): Result<U, E>;

Defined in: result.ts:86

Type Parameters

Type Parameter
U

Parameters

Parameter	Type
_fn	(value) => U

Returns

Result<U, E>

mapError()

mapError<F>(fn): Result<T, F>;

Defined in: result.ts:90

Type Parameters

Type Parameter
F

Parameters

Parameter	Type
fn	(error) => F

Returns

Result<T, F>

match()

match<R>(pattern): R;

Defined in: result.ts:110

Type Parameters

Type Parameter
R

Parameters

Parameter	Type
pattern	{ Error: (error) => R; Ok: (value) => R; }
pattern.Error	(error) => R
pattern.Ok	(value) => R

Returns

R

toOption()

toOption(): Option<T>;

Defined in: result.ts:114

Returns

Option<T>

---

Future

Defined in: future.ts:8

Future type representing an asynchronous computation This is a custom implementation compatible with Temporal workflows

Type Parameters

Type Parameter
T

Implements

• Promise<T>

Properties

Property	Modifier	Type	Default value	Defined in
[toStringTag]	readonly	"Future"	"Future"	future.ts:12

Methods

catch()

catch<TResult>(onRejected?): Promise<T | TResult>;

Defined in: future.ts:189

Attaches a callback for only the rejection of the Promise.

Type Parameters

Type Parameter	Default type
TResult	never

Parameters

Parameter	Type
onRejected?	(reason) => TResult | PromiseLike<TResult> | null

Returns

Promise<T | TResult>

A Promise for the completion of the callback.

Implementation of

Promise.catch

finally()

finally(onFinally?): Promise<T>;

Defined in: future.ts:195

Attaches a callback that is invoked when the Promise is settled (fulfilled or rejected). The resolved value cannot be modified from the callback.

Parameters

Parameter	Type
onFinally?	() => void | null

Returns

Promise<T>

A Promise for the completion of the callback.

Implementation of

Promise.finally

flatMap()

flatMap<U>(fn): Future<U>;

Defined in: future.ts:95

FlatMap the result of the Future

Type Parameters

Type Parameter
U

Parameters

Parameter	Type
fn	(value) => Future<U>

Returns

Future<U>

flatMapOk()

flatMapOk<V, E, U>(this, fn): Future<Result<U, E>>;

Defined in: future.ts:126

FlatMap over a Result within a Future

Type Parameters

Type Parameter
V
E
U

Parameters

Parameter	Type
this	Future<Result<V, E>>
fn	(value) => Future<Result<U, E>>

Returns

Future<Result<U, E>>

map()

map<U>(fn): Future<U>;

Defined in: future.ts:88

Map the result of the Future

Type Parameters

Type Parameter
U

Parameters

Parameter	Type
fn	(value) => U

Returns

Future<U>

mapError()

mapError<V, E, F>(this, fn): Future<Result<V, F>>;

Defined in: future.ts:114

Map over an error in a Result within a Future

Type Parameters

Type Parameter
V
E
F

Parameters

Parameter	Type
this	Future<Result<V, E>>
fn	(error) => F

Returns

Future<Result<V, F>>

mapOk()

mapOk<V, U, E>(this, fn): Future<Result<U, E>>;

Defined in: future.ts:102

Map over a Result within a Future

Type Parameters

Type Parameter
V
U
E

Parameters

Parameter	Type
this	Future<Result<V, E>>
fn	(value) => U

Returns

Future<Result<U, E>>

tap()

tap(fn): Future<T>;

Defined in: future.ts:143

Tap into the Future value without changing it

Parameters

Parameter	Type
fn	(value) => void

Returns

Future<T>

tapError()

tapError<V, E>(this, fn): Future<Result<V, E>>;

Defined in: future.ts:164

Tap into Error values in a Result

Type Parameters

Type Parameter
V
E

Parameters

Parameter	Type
this	Future<Result<V, E>>
fn	(error) => void

Returns

Future<Result<V, E>>

tapOk()

tapOk<V, E>(this, fn): Future<Result<V, E>>;

Defined in: future.ts:153

Tap into Ok values in a Result

Type Parameters

Type Parameter
V
E

Parameters

Parameter	Type
this	Future<Result<V, E>>
fn	(value) => void

Returns

Future<Result<V, E>>

then()

then<TResult1, TResult2>(onFulfilled?, onRejected?): Promise<TResult1 | TResult2>;

Defined in: future.ts:182

Attaches callbacks for the resolution and/or rejection of the Promise.

Type Parameters

Type Parameter	Default type
TResult1	T
TResult2	never

Parameters

Parameter	Type
onFulfilled?	(value) => TResult1 | PromiseLike<TResult1> | null
onRejected?	(reason) => TResult2 | PromiseLike<TResult2> | null

Returns

Promise<TResult1 | TResult2>

A Promise for the completion of which ever callback is executed.

Implementation of

Promise.then

toPromise()

toPromise(): Promise<T>;

Defined in: future.ts:175

Convert to a Promise (for await)

Returns

Promise<T>

all()

static all<T>(futures): Future<T[]>;

Defined in: future.ts:56

Combine multiple Futures into one

Type Parameters

Type Parameter
T

Parameters

Parameter	Type
futures	Future<T>[]

Returns

Future<T[]>

fromAsync()

static fromAsync<T>(fn): Future<T>;

Defined in: future.ts:81

Create a Future from an async function.

Prefer this over Future.make when the executor is async, as it properly propagates rejections instead of leaving the Future pending on unhandled errors.

Type Parameters

Type Parameter
T

Parameters

Parameter	Type
fn	() => Promise<T>

Returns

Future<T>

Example

const future = Future.fromAsync(async () => {
  const data = await fetchSomething();
  return data;
});

fromPromise()

static fromPromise<T>(promise): Future<Result<T, unknown>>;

Defined in: future.ts:38

Create a Future from a Promise

Type Parameters

Type Parameter
T

Parameters

Parameter	Type
promise	Promise<T>

Returns

Future<Result<T, unknown>>

make()

static make<T>(executor): Future<T>;

Defined in: future.ts:21

Create a Future from an executor function

Type Parameters

Type Parameter
T

Parameters

Parameter	Type
executor	(resolve) => void

Returns

Future<T>

race()

static race<T>(futures): Future<T>;

Defined in: future.ts:63

Race multiple Futures

Type Parameters

Type Parameter
T

Parameters

Parameter	Type
futures	Future<T>[]

Returns

Future<T>

reject()

static reject<T>(error): Future<T>;

Defined in: future.ts:49

Create a rejected Future

Type Parameters

Type Parameter	Default type
T	never

Parameters

Parameter	Type
error	unknown

Returns

Future<T>

value()

static value<T>(value): Future<T>;

Defined in: future.ts:31

Create a Future from a value

Type Parameters

Type Parameter
T

Parameters

Parameter	Type
value	T

Returns

Future<T>

---

Ok

Defined in: result.ts:15

Ok variant representing a successful result

Type Parameters

Type Parameter
T
E

Constructors

Constructor

new Ok<T, E>(value): Ok<T, E>;

Defined in: result.ts:19

Parameters

Parameter	Type
value	T

Returns

Ok<T, E>

Properties

Property	Modifier	Type	Defined in
tag	readonly	"Ok"	result.ts:16
value	readonly	T	result.ts:17

Methods

flatMap()

flatMap<U>(fn): Result<U, E>;

Defined in: result.ts:39

Type Parameters

Type Parameter
U

Parameters

Parameter	Type
fn	(value) => Result<U, E>

Returns

Result<U, E>

flatMapOk()

flatMapOk<U>(fn): Result<U, E>;

Defined in: result.ts:43

Type Parameters

Type Parameter
U

Parameters

Parameter	Type
fn	(value) => Result<U, E>

Returns

Result<U, E>

getOr()

getOr(_defaultValue): T;

Defined in: result.ts:47

Parameters

Parameter	Type
_defaultValue	T

Returns

T

getWithDefault()

getWithDefault(_defaultValue): T;

Defined in: result.ts:51

Parameters

Parameter	Type
_defaultValue	T

Returns

T

isError()

isError(): this is Err<T, E>;

Defined in: result.ts:27

Returns

this is Err<T, E>

isOk()

isOk(): this is Ok<T, E>;

Defined in: result.ts:23

Returns

this is Ok<T, E>

map()

map<U>(fn): Result<U, E>;

Defined in: result.ts:31

Type Parameters

Type Parameter
U

Parameters

Parameter	Type
fn	(value) => U

Returns

Result<U, E>

mapError()

mapError<F>(_fn): Result<T, F>;

Defined in: result.ts:35

Type Parameters

Type Parameter
F

Parameters

Parameter	Type
_fn	(error) => F

Returns

Result<T, F>

match()

match<R>(pattern): R;

Defined in: result.ts:55

Type Parameters

Type Parameter
R

Parameters

Parameter	Type
pattern	{ Error: (error) => R; Ok: (value) => R; }
pattern.Error	(error) => R
pattern.Ok	(value) => R

Returns

R

toOption()

toOption(): Option<T>;

Defined in: result.ts:59

Returns

Option<T>

Type Aliases

Option

type Option<T> = 
  | {
  tag: "Some";
  value: T;
}
  | {
  tag: "None";
};

Defined in: result.ts:122

Option type for Result.toOption()

Type Parameters

Type Parameter
T

---

Result

type Result<T, E> = Ok<T, E> | Err<T, E>;

Defined in: result.ts:10

Result type representing either a successful value (Ok) or an error (Err) This is a custom implementation compatible with Temporal workflows

Note: The error variant class is named Err internally to avoid shadowing the global Error constructor. The public API still uses Result.Error() as a factory and isError() as a type guard for backward compatibility.

Type Parameters

Type Parameter
T
E

Variables

Result

Result: object;

Defined in: result.ts:10

Result namespace with factory methods

Type Declaration

Name	Type	Defined in
all()	<T, E>(results) => Result<T[], E>	result.ts:152
Error()	<T, E>(error) => Result<T, E>	result.ts:129
fromAsyncExecution()	<T, E>(fn) => Promise<Result<T, E>>	result.ts:142
fromExecution()	<T, E>(fn) => Result<T, E>	result.ts:134
isError()	<T, E>(result) => result is Err<T, E>	result.ts:132
isOk()	<T, E>(result) => result is Ok<T, E>	result.ts:131
Ok()	<T, E>(value) => Result<T, E>	result.ts:128