Class: Result<T, E, Success>

A type used to express computations that can fail, it can be used for returning and propagating errors. This is a type union with the variants Ok(T), representing success and containing a value, and Err(E), representing error and containing an error value.

Typeparam

T The result's type.

Typeparam

E The error's type.

See

https://doc.rust-lang.org/std/result/index.html

Type Parameters

Type Parameter	Default type
`T`	-
`E`	-
`Success` extends `boolean`	`boolean`

Constructors

new Result()

private new Result<T, E, Success>(value: If<Success, T, E>, success: Success): Result<T, E, Success>

Parameters

Parameter	Type
`value`	`If`<`Success`, `T`, `E`>
`success`	`Success`

Returns

Result<T, E, Success>

Defined in

projects/utilities/packages/result/src/lib/Result.ts:28

Properties

STATUS

protected __STATUS__: Success

Internal

Branded value to ensure Success is typed correctly.

Defined in

projects/utilities/packages/result/src/lib/Result.ts:23

[SuccessProperty]

private readonly [SuccessProperty]: Success

Defined in

projects/utilities/packages/result/src/lib/Result.ts:26

[ValueProperty]

private readonly [ValueProperty]: If<Success, T, E>

Defined in

projects/utilities/packages/result/src/lib/Result.ts:25

Accessors

[toStringTag]

Get Signature

get [toStringTag](): If<Success, "Ok", "Err">

Returns

If<Success, "Ok", "Err">

Defined in

projects/utilities/packages/result/src/lib/Result.ts:993

Methods

[iterator]()

[iterator](): Generator<T, any, unknown>

Returns an iterator over the possibly contained value.

The iterator yields one value if the result is Ok, otherwise none.

Returns

Generator<T, any, unknown>

Examples

const x = ok(7);
for (const value of x) {
  console.log(value);
}
// Logs 7

const x = err('Nothing!');
for (const value of x) {
  console.log(value);
}
// Doesn't log

See

IResult.iter
https://doc.rust-lang.org/std/result/enum.Result.html#method.iter

Defined in

projects/utilities/packages/result/src/lib/Result.ts:989

and()

and<OutputResult>(result: OutputResult): If<Success, OutputResult, Err<E, any>>

Returns result if the result is Ok, otherwise returns the Err value of itself.

Type Parameters

Type Parameter
`OutputResult` extends `Any`

Parameters

Parameter	Type	Description
`result`	`OutputResult`	The result to check.

Returns

If<Success, OutputResult, Err<E, any>>

Examples

const x: Result<number, string> = ok(2);
const y: Result<string, string> = err('Late error');
assert.equal(x.and(y), err('Late error'));

const x: Result<number, string> = err('Early error');
const y: Result<string, string> = err('Late error');
assert.equal(x.and(y), err('Early error'));

const x: Result<number, string> = ok(2);
const y: Result<string, string> = ok('Hello');
assert.equal(x.and(y), ok('Hello'));

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.and

Defined in

projects/utilities/packages/result/src/lib/Result.ts:682

andThen()

andThen<OutputResult>(cb: (value: T) => OutputResult): If<Success, OutputResult, Err<E, any>>

Calls cb if the result is Ok, otherwise returns the Err value of self.

This function can be used for control flow based on Result values.

Type Parameters

Type Parameter
`OutputResult` extends `Any`

Parameters

Parameter	Type	Description
`cb`	(`value`: `T`) => `OutputResult`	The predicate.

Returns

If<Success, OutputResult, Err<E, any>>

Example

function fractionOf4(value: number) {
  return value === 0 ? err('overflowed') : ok(4 / value);
}

assert.equal(ok(2).andThen(fractionOf4), ok(4));
assert.equal(ok(0).andThen(fractionOf4), err('overflowed'));
assert.equal(err('not a number').andThen(fractionOf4), err('not a number'));

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.and_then

Defined in

projects/utilities/packages/result/src/lib/Result.ts:705

contains()

contains(this, value)

contains<Value>(this: Ok<T, any>, value: Value): this is Ok<Value, any>

Returns true if the result is an Ok and the given value strict equals it.

Type Parameters

Type Parameter
`Value`

Parameters

Parameter	Type	Description
`this`	`Ok`<`T`, `any`>	-
`value`	`Value`	The value to compare.

Returns

this is Ok<Value, any>

Examples

const x: Result<number, string> = ok(2);
assert.equal(x.contains(2), true);

const x: Result<number, string> = ok(3);
assert.equal(x.contains(2), false);

const x: Result<number, string> = err('Some error message');
assert.equal(x.contains(2), false);

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.contains

Defined in

projects/utilities/packages/result/src/lib/Result.ts:792

contains(this, value)

contains(this: Err<E, any>, value: T): false

Parameters

Parameter	Type
`this`	`Err`<`E`, `any`>
`value`	`T`

Returns

false

Defined in

projects/utilities/packages/result/src/lib/Result.ts:793

containsErr()

containsErr(this, error)

containsErr(this: Ok<T, any>, error: E): false

Returns true if the result is an Err and the given error strict equals it.

Parameters

Parameter	Type	Description
`this`	`Ok`<`T`, `any`>	-
`error`	`E`	The error to compare.

Returns

false

Examples

const x: Result<number, string> = ok(2);
assert.equal(x.containsErr('Some error message'), false);

const x: Result<number, string> = err('Some error message');
assert.equal(x.containsErr('Some error message'), true);

const x: Result<number, string> = err('Some other error message');
assert.equal(x.containsErr('Some error message'), false);

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.contains_err

Defined in

projects/utilities/packages/result/src/lib/Result.ts:820

containsErr(this, error)

containsErr<Value>(this: Err<E, any>, error: Value): this is Err<Value, any>

Type Parameters

Type Parameter
`Value`

Parameters

Parameter	Type
`this`	`Err`<`E`, `any`>
`error`	`Value`

Returns

this is Err<Value, any>

Defined in

projects/utilities/packages/result/src/lib/Result.ts:821

eq()

eq<OtherValue, OtherError, OtherSuccess>(other: Result<OtherValue, OtherError, OtherSuccess>): this is Result<OtherValue, OtherError, OtherSuccess>

Checks whether or not other equals with self.

Type Parameters

Type Parameter
`OtherValue`
`OtherError`
`OtherSuccess` extends `boolean`

Parameters

Parameter	Type	Description
`other`	`Result`<`OtherValue`, `OtherError`, `OtherSuccess`>	The other result to compare.

Returns

this is Result<OtherValue, OtherError, OtherSuccess>

See

https://doc.rust-lang.org/std/cmp/trait.PartialEq.html#tymethod.eq

Defined in

projects/utilities/packages/result/src/lib/Result.ts:918

err()

err(): If<Success, None, Some<E>>

Converts from Result<T, E> to Option<E>.

Converts itself into an Option<E>, and discarding the successful value, if any.

Returns

If<Success, None, Some<E>>

Examples

const x: Result<number, string> = ok(2);
assert.equal(x.err(), none);

const x: Result<number, string> = err('Some error message');
assert.equal(x.err(), 'Some error message');

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.err

Defined in

projects/utilities/packages/result/src/lib/Result.ts:168

expect()

expect(message: string): If<Success, T, never>

Returns the contained Ok value.

If the value is an Err, it throws a ResultError with the given message and the content of the Err.

Parameters

Parameter	Type	Description
`message`	`string`	The message for the error.

Returns

If<Success, T, never>

Examples

const x = ok(2);
assert.equal(x.expect('Whoops!'), 2);

const x = err('Emergency failure');
assert.throws(() => x.expect('Whoops!'), {
  name: 'ResultError',
  message: 'Whoops',
  value: 'Emergency failure'
});

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.expect

Defined in

projects/utilities/packages/result/src/lib/Result.ts:479

expectErr()

expectErr(message: string): If<Success, never, E>

Returns the contained Err value.

If the value is an Ok, it throws a ResultError with the given message and the content of the Ok.

Parameters

Parameter	Type	Description
`message`	`string`	The message for the error.

Returns

If<Success, never, E>

Examples

const x = ok(2);
assert.throws(() => x.expectErr('Whoops!'), {
  name: 'ResultError',
  message: 'Whoops',
  value: 2
});

const x = err('Emergency failure');
assert.equal(x.expectErr('Whoops!'), 'Emergency failure');

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.expect_err

Defined in

projects/utilities/packages/result/src/lib/Result.ts:507

flatten()

flatten<InnerResult>(this: Result<InnerResult, E, Success>): If<Success, InnerResult, Err<E, any>>

Converts from Result<Result<T, E>, E> to Result<T, E>.

Type Parameters

Type Parameter
`InnerResult` extends `Any`

Parameters

Parameter	Type
`this`	`Result`<`InnerResult`, `E`, `Success`>

Returns

If<Success, InnerResult, Err<E, any>>

Examples

const x: Result<Result<string, number>, number> = ok(ok('Hello'));
assert.equal(x.flatten(), ok('Hello'));

const x: Result<Result<string, number>, number> = ok(err(6));
assert.equal(x.flatten(), err(6));

const x: Result<Result<string, number>, number> = err(6);
assert.equal(x.flatten(), err(6));

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.flatten

Defined in

projects/utilities/packages/result/src/lib/Result.ts:870

inspect()

inspect(cb: (value: T) => unknown): this

Calls the provided closure with a reference to the contained value (if Ok).

Parameters

Parameter	Type	Description
`cb`	(`value`: `T`) => `unknown`	The predicate.

Returns

this

Examples

ok(2).inspect(console.log);
// Logs: 2

err('Some error message').inspect(console.log);
// Doesn't log

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.inspect

Defined in

projects/utilities/packages/result/src/lib/Result.ts:354

inspectAsync()

inspectAsync(cb: (value: T) => unknown): Promise<Result<T, E, Success>>

Calls the provided closure with a reference to the contained value (if Ok) and awaits it.

Parameters

Parameter	Type	Description
`cb`	(`value`: `T`) => `unknown`	The predicate.

Returns

Promise<Result<T, E, Success>>

Examples

await ok(2).inspectAsync(console.log);
// Logs: 2

await err('Some error message').inspectAsync(console.log);
// Doesn't log

Note

This is an extension not supported in Rust

Defined in

projects/utilities/packages/result/src/lib/Result.ts:377

inspectErr()

inspectErr(cb: (error: E) => unknown): this

Calls the provided closure with a reference to the contained error (if Err).

Parameters

Parameter	Type	Description
`cb`	(`error`: `E`) => `unknown`	The predicate.

Returns

this

Examples

ok(2).inspectErr(console.log);
// Doesn't log

err('Some error message').inspectErr(console.log);
// Logs: Some error message

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.inspect_err

Defined in

projects/utilities/packages/result/src/lib/Result.ts:400

inspectErrAsync()

inspectErrAsync(cb: (error: E) => unknown): Promise<Result<T, E, Success>>

Calls the provided closure with a reference to the contained error (if Err) and awaits it.

Parameters

Parameter	Type	Description
`cb`	(`error`: `E`) => `unknown`	The predicate.

Returns

Promise<Result<T, E, Success>>

Examples

await ok(2).inspectErrAsync(console.log);
// Doesn't log

await err('Some error message').inspectErrAsync(console.log);
// Logs: Some error message

Note

This is an extension not supported in Rust

Defined in

projects/utilities/packages/result/src/lib/Result.ts:423

intoOkOrErr()

intoOkOrErr(): If<Success, T, E>

Returns the Ok value if self is Ok, and the Err value if self is Err.

Returns

If<Success, T, E>

Examples

let x: Result<number, number> = ok(3);
assert.equal(x.intoOkOrErr(), 3);

let x: Result<number, number> = err(4);
assert.equal(x.intoOkOrErr(), 4);

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.into_ok_or_err

Defined in

projects/utilities/packages/result/src/lib/Result.ts:890

intoPromise()

intoPromise(): If<Success, Promise<Ok<Awaited<T>, any>>, Promise<Err<Awaited<E>, any>>>

Returns a Promise object with the awaited value (if Ok) or the awaited error (if Err).

Returns

If<Success, Promise<Ok<Awaited<T>, any>>, Promise<Err<Awaited<E>, any>>>

Example

let x = ok(Promise.resolve(3));
assert.equal(await x.intoPromise(), ok(3));

Note

This is an extension not supported in Rust

Defined in

projects/utilities/packages/result/src/lib/Result.ts:905

isErr()

isErr(): this is Err<E, T>

Returns true if the result is Err.

Returns

this is Err<E, T>

Examples

const x = ok(-3);
assert.equal(x.isErr(), false);

const x = err('Some error message');
assert.equal(x.isErr(), true);

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.is_err

Defined in

projects/utilities/packages/result/src/lib/Result.ts:96

isErrAnd()

isErrAnd(cb)

isErrAnd<R>(cb: (error: E) => error is R): this is Err<R, T>

Returns true if the result is Err and the value inside of it matches a predicate.

Type Parameters

Type Parameter
`R`

Parameters

Parameter	Type	Description
`cb`	(`error`: `E`) => `error is R`	The predicate.

Returns

this is Err<R, T>

Examples

const x = ok(2);
assert.equal(x.isErrAnd((error) => error instanceof TypeError), false);

const x = err(new Error('Some error message'));
assert.equal(x.isErrAnd((error) => error instanceof TypeError), false);

const x = err(new TypeError('Some error message'));
assert.equal(x.isErrAnd((error) => error instanceof TypeError), true);

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.is_err_and

Defined in

projects/utilities/packages/result/src/lib/Result.ts:122

isErrAnd(cb)

isErrAnd<R>(cb: (error: E) => R): this is Err<E, T> & R

Type Parameters

Type Parameter
`R` extends `boolean`

Parameters

Parameter	Type
`cb`	(`error`: `E`) => `R`

Returns

this is Err<E, T> & R

Defined in

projects/utilities/packages/result/src/lib/Result.ts:123

isOk()

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

Returns true if the result is Ok.

Returns

this is Ok<T, E>

Examples

const x = ok(-3);
assert.equal(x.isOk(), true);

const x = err('Some error message');
assert.equal(x.isOk(), false);

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.is_ok

Defined in

projects/utilities/packages/result/src/lib/Result.ts:49

isOkAnd()

isOkAnd(cb)

isOkAnd<R>(cb: (value: T) => value is R): this is Ok<R, E>

Returns true if the result is Ok and the value inside of it matches a predicate.

Type Parameters

Type Parameter
`R`

Parameters

Parameter	Type
`cb`	(`value`: `T`) => `value is R`

Returns

this is Ok<R, E>

Examples

const x = ok(2);
assert.equal(x.isOkAnd((value) => value > 1), true);

const x = ok(0);
assert.equal(x.isOkAnd((value) => value > 1), false);

const x = err('Some error message');
assert.equal(x.isOkAnd((value) => value > 1), false);

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.is_ok_and

Defined in

projects/utilities/packages/result/src/lib/Result.ts:74

isOkAnd(cb)

isOkAnd<R>(cb: (value: T) => R): this is Ok<T, E> & R

Type Parameters

Type Parameter
`R` extends `boolean`

Parameters

Parameter	Type
`cb`	(`value`: `T`) => `R`

Returns

this is Ok<T, E> & R

Defined in

projects/utilities/packages/result/src/lib/Result.ts:75

iter()

iter(): Generator<T, any, unknown>

Returns an iterator over the possibly contained value.

The iterator yields one value if the result is Ok, otherwise none.

Returns

Generator<T, any, unknown>

Examples

const x = ok(7);
for (const value of x.iter()) {
  console.log(value);
}
// Logs 7

const x = err('Nothing!');
for (const value of x.iter()) {
  console.log(value);
}
// Doesn't log

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.iter

Defined in

projects/utilities/packages/result/src/lib/Result.ts:452

map()

map<OutputValue>(cb: (value: T) => OutputValue): If<Success, Ok<OutputValue, E>, Err<E, any>>

Maps a Result<T, E> to Result<U, E> by applying a function to a contained Ok value, leaving an Err value untouched.

Type Parameters

Type Parameter
`OutputValue`

Parameters

Parameter	Type	Description
`cb`	(`value`: `T`) => `OutputValue`	The predicate.

Returns

If<Success, Ok<OutputValue, E>, Err<E, any>>

Examples

const x: Result<number, string> = ok(2);
assert.equal(x.map((value) => value * 2), ok(4));

const x: Result<number, string> = err('Some error message');
assert.equal(x.map((value) => value * 2), err('Some error message'));

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.map

Defined in

projects/utilities/packages/result/src/lib/Result.ts:190

mapErr()

mapErr<OutputError>(cb: (error: E) => OutputError): If<Success, Ok<T, any>, Err<OutputError, any>>

Maps a Result<T, E> to Result<T, F> by applying a function to a contained Err value, leaving an Ok value untouched.

This function can be used to pass through a successful result while handling an error.

Type Parameters

Type Parameter
`OutputError`

Parameters

Parameter	Type	Description
`cb`	(`error`: `E`) => `OutputError`	The predicate.

Returns

If<Success, Ok<T, any>, Err<OutputError, any>>

Examples

const x: Result<number, Error> = ok(2);
assert.equal(x.mapErr((error) => error.message), ok(2));

const x: Result<number, Error> = err(new Error('Some error message'));
assert.equal(x.mapErr((error) => error.message), err('Some error message'));

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.map_err

Defined in

projects/utilities/packages/result/src/lib/Result.ts:300

mapErrInto()

mapErrInto<OutputResult>(cb: (error: E) => OutputResult): If<Success, Ok<T, any>, OutputResult>

Maps a Result<T, E> to Result<T, F> by applying a function to a contained Err value, leaving an Ok value untouched.

This function can be used to pass through a successful result while handling an error.

Unlike mapErr, this method does not wrap the returned value inside Err, but instead, it returns the returned value.

Type Parameters

Type Parameter
`OutputResult` extends `Any`

Parameters

Parameter	Type	Description
`cb`	(`error`: `E`) => `OutputResult`	The predicate.

Returns

If<Success, Ok<T, any>, OutputResult>

Examples

const x: Result<number, Error> = ok(2);
assert.equal(x.mapErrInto((error) => err(error.message)), ok(2));

const x: Result<number, Error> = err(new Error('Some error message'));
assert.equal(x.mapErrInto((error) => err(error.message)), err('Some error message'));

const x: Result<number, Error> = err(new Error('Some error message'));
assert.equal(x.mapErrInto((error) => ok(4)), ok(4));

Note

This is an extension not supported in Rust

Defined in

projects/utilities/packages/result/src/lib/Result.ts:332

mapInto()

mapInto<OutputResult>(cb: (value: T) => OutputResult): If<Success, OutputResult, Err<E, any>>

Maps a Result<T, E> to Result<T, F> by applying a function to a contained Ok value, leaving an Err value untouched.

Unlike map, this method does not wrap the returned value inside Ok, but instead, it returns the returned value.

Type Parameters

Type Parameter
`OutputResult` extends `Any`

Parameters

Parameter	Type	Description
`cb`	(`value`: `T`) => `OutputResult`	The predicate.

Returns

If<Success, OutputResult, Err<E, any>>

Examples

const x: Result<number, string> = ok(2);
assert.equal(x.mapInto((value) => ok(value * value)), ok(4));

const x: Result<number, string> = ok(0);
assert.equal(
  x.mapInto((value) => (value === 0 ? err('zero is not divisible') : ok(1 / value))),
  err('zero is not divisible')
);

const x: Result<number, string> = err('Some error message');
assert.equal(x.mapInto((value) => ok(4)), err('Some error message'));

Note

This is an extension not supported in Rust

Defined in

projects/utilities/packages/result/src/lib/Result.ts:223

mapOr()

mapOr<MappedOutputValue, DefaultOutputValue>(defaultValue: DefaultOutputValue, cb: (value: T) => MappedOutputValue): If<Success, MappedOutputValue, DefaultOutputValue>

Returns the provided default (if Err), or applies a function to the contained value (if Ok),

Arguments passed to mapOr are eagerly evaluated; if you are passing the result of a function call, it is recommended to use mapOrElse, which is lazily evaluated.

Type Parameters

Type Parameter
`MappedOutputValue`
`DefaultOutputValue`

Parameters

Parameter	Type	Description
`defaultValue`	`DefaultOutputValue`	The default value to use.
`cb`	(`value`: `T`) => `MappedOutputValue`	The predicate.

Returns

If<Success, MappedOutputValue, DefaultOutputValue>

Examples

const x = ok('hello');
assert.equal(x.mapOr(42, (value) => value.length), 5);

const x = err('Some error message');
assert.equal(x.mapOr(42, (value) => value.length), 42);

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.map_or

Defined in

projects/utilities/packages/result/src/lib/Result.ts:248

mapOrElse()

mapOrElse<OutputValue, OutputError>(op: (error: E) => OutputError, cb: (value: T) => OutputValue): If<Success, OutputValue, OutputError>

Maps a Result<T, E> to U by applying fallback function default to a contained Err value, or function cb to a contained Ok value.

This function can be used to unpack a successful result while handling an error.

Type Parameters

Type Parameter
`OutputValue`
`OutputError`

Parameters

Parameter	Type	Description
`op`	(`error`: `E`) => `OutputError`	The predicate that is run on `Err`.
`cb`	(`value`: `T`) => `OutputValue`	The predicate that is run on `Ok`.

Returns

If<Success, OutputValue, OutputError>

Examples

const x: Result<string, string> = ok('hello');
assert.equal(x.mapOrElse((error) => error.length, (value) => value.length), 5);

const x: Result<string, string> = err('Some error message');
assert.equal(x.mapOrElse((error) => error.length, (value) => value.length), 18);

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.map_or_else

Defined in

projects/utilities/packages/result/src/lib/Result.ts:276

match()

match<OkValue, ErrValue>(branches: object): If<Success, OkValue, ErrValue>

Runs ok function if self is Ok, otherwise runs err function.

Type Parameters

Type Parameter
`OkValue`
`ErrValue`

Parameters

Parameter	Type	Description
`branches`	`object`	The branches to match.
`branches.err`	-
`branches.ok`	-

Returns

If<Success, OkValue, ErrValue>

Examples

const result = ok(4).match({
  ok: (v) => v,
  err: () => 0
});
assert.equal(result, 4);

const result = err('Hello').match({
  ok: (v) => v,
  err: () => 0
});
assert.equal(result, 0);

Defined in

projects/utilities/packages/result/src/lib/Result.ts:956

ne()

ne(other: Result<T, E, boolean>): boolean

Checks whether or not other doesn't equal with self.

Parameters

Parameter	Type	Description
`other`	`Result`<`T`, `E`, `boolean`>	The other result to compare.

Returns

boolean

See

https://doc.rust-lang.org/std/cmp/trait.PartialEq.html#method.ne

Defined in

projects/utilities/packages/result/src/lib/Result.ts:931

ok()

ok(): If<Success, Some<T>, None>

Converts from Result<T, E> to Option<T>.

Converts itself into an Option<T>, and discarding the error, if any.

Returns

If<Success, Some<T>, None>

Examples

const x: Result<number, string> = ok(2);
assert.equal(x.ok(), some(2));

const x: Result<number, string> = err('Some error message');
assert.equal(x.ok(), none);

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.ok

Defined in

projects/utilities/packages/result/src/lib/Result.ts:146

or()

or<OutputResult>(result: OutputResult): If<Success, Ok<T, any>, OutputResult>

Return result if the result is Err, otherwise returns the Ok value of self.

Arguments passed to or are eagerly evaluated; if you are passing the result of a function call, it is recommended to use orElse, which is lazily evaluated.

Type Parameters

Type Parameter
`OutputResult` extends `Any`

Parameters

Parameter	Type	Description
`result`	`OutputResult`	The result to check.

Returns

If<Success, Ok<T, any>, OutputResult>

Examples

const x: Result<number, string> = ok(2);
const y: Result<number, string> = err('Late error');
assert.equal(x.or(y), ok(2));

const x: Result<number, string> = err('Early error');
const y: Result<number, string> = ok(2);
assert.equal(x.or(y), ok(2));

const x: Result<number, string> = err('Early error');
const y: Result<number, string> = err('Late error');
assert.equal(x.or(y), err('Late error'));

const x: Result<number, string> = ok(2);
const y: Result<number, string> = ok(100);
assert.equal(x.or(y), ok(2));

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.or

Defined in

projects/utilities/packages/result/src/lib/Result.ts:743

orElse()

orElse<OutputResult>(cb: (error: E) => OutputResult): If<Success, Ok<T, any>, OutputResult>

Calls cb if the result is Err, otherwise returns the Ok value of self.

This function can be used for control flow based on result values.

Type Parameters

Type Parameter
`OutputResult` extends `Any`

Parameters

Parameter	Type	Description
`cb`	(`error`: `E`) => `OutputResult`	The predicate.

Returns

If<Success, Ok<T, any>, OutputResult>

Example

const square = (x: number): Result<number, string> => ok(x * x);
const wrapErr = (x: number): Result<number, string> => err(x);

assert.equal(ok(2).orElse(square).orElse(square), ok(2));
assert.equal(ok(2).orElse(wrapErr).orElse(square), ok(2));
assert.equal(err(3).orElse(square).orElse(wrapErr), ok(9));
assert.equal(err(3).orElse(wrapErr).orElse(wrapErr), err(3));

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.or_else

Defined in

projects/utilities/packages/result/src/lib/Result.ts:766

transpose()

transpose<InnerValue>(this: Result<Option<InnerValue, boolean>, E, Success>): If<Success, Option<Ok<InnerValue, any>, boolean>, Some<Err<E, any>>>

Transposes a Result of an Option into an Option of a Result.

ok(none) will be mapped to none. ok(some(v)) and err(e) will be mapped to some(ok(v)) and some(err(e)).

Type Parameters

Type Parameter
`InnerValue`

Parameters

Parameter	Type
`this`	`Result`<`Option`<`InnerValue`, `boolean`>, `E`, `Success`>

Returns

If<Success, Option<Ok<InnerValue, any>, boolean>, Some<Err<E, any>>>

Example

const x: Result<Option<number>, Error> = ok(some(5));
const y: Option<Result<number, Error>> = some(ok(5));
assert.equal(x.transpose(), y);

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.transpose

Defined in

projects/utilities/packages/result/src/lib/Result.ts:840

unwrap()

unwrap(): If<Success, T, never>

Returns the contained Ok value.

If the value is an Err, it throws a ResultError with the message, and the content of the Err.

Returns

If<Success, T, never>

Examples

const x = ok(2);
assert.equal(x.unwrap(), 2);

const x = err('Emergency failure');
assert.throws(() => x.unwrap(), {
  name: 'ResultError',
  message: 'Unwrap failed',
  value: 'Emergency failure'
});

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.unwrap

Defined in

projects/utilities/packages/result/src/lib/Result.ts:538

unwrapErr()

unwrapErr(): If<Success, never, E>

Returns the contained Err value.

If the value is an Ok, it throws a ResultError with the message, and the content of the Ok.

Returns

If<Success, never, E>

Examples

const x = ok(2);
assert.throws(() => x.unwrapErr(), {
  name: 'ResultError',
  message: 'Unwrap failed',
  value: 2
});

const x = err('Emergency failure');
assert.equal(x.unwrapErr(), 'Emergency failure');

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.unwrap_err

Defined in

projects/utilities/packages/result/src/lib/Result.ts:569

unwrapOr()

unwrapOr<OutputValue>(defaultValue: OutputValue): If<Success, T, OutputValue>

Returns the contained Ok value or the provided default.

Arguments passed to unwrapOr are eagerly evaluated; if you are passing the result of a function call, it is recommended to use unwrapOrElse, which is lazily evaluated.

Type Parameters

Type Parameter
`OutputValue`

Parameters

Parameter	Type	Description
`defaultValue`	`OutputValue`	The default value.

Returns

If<Success, T, OutputValue>

Examples

const x: Result<number, string> = ok(9);
assert.equal(x.unwrapOr(2), 9);

const x: Result<number, string> = err('Error');
assert.equal(x.unwrapOr(2), 2);

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.unwrap_or

Defined in

projects/utilities/packages/result/src/lib/Result.ts:599

unwrapOrElse()

unwrapOrElse<OutputValue>(op: (error: E) => OutputValue): If<Success, T, OutputValue>

Returns the contained Ok value or computes it from a closure.

Type Parameters

Type Parameter
`OutputValue`

Parameters

Parameter	Type	Description
`op`	(`error`: `E`) => `OutputValue`	The predicate.

Returns

If<Success, T, OutputValue>

Example

const count = (x: string) => x.length;

assert.equal(ok(2).unwrapOrElse(count), 2);
assert.equal(err('hello').unwrapOrElse(count), 5);

See

https://doc.rust-lang.org/std/result/enum.Result.html#method.unwrap_or_else

Defined in

projects/utilities/packages/result/src/lib/Result.ts:622

unwrapRaw()

unwrapRaw(): If<Success, T, never>

Returns the contained Ok value.

If the value is an Err, it throws the contained error.

Returns

If<Success, T, never>

Examples

const x = ok(2);
assert.equal(x.unwrapRaw(), 2);

const x = err('Emergency failure');
assert.throws(() => x.unwrapRaw(), {
  name: 'Error',
  message: 'Unwrap failed',
  value: 'Emergency failure'
});

Defined in

projects/utilities/packages/result/src/lib/Result.ts:650

[hasInstance]()

static [hasInstance](instance: unknown): boolean

Checks if the instance object is an instance of Result, or if it is a Result-like object. This override exists to interoperate with other versions of this class, such as the one coming from another version of this library or from a different build.

Parameters

Parameter	Type	Description
`instance`	`unknown`	The instance to check.

Returns

boolean

Whether or not the instance is a Result.

Example

import { Result } from '@sapphire/result';
const { ok } = require('@sapphire/result');

ok(2) instanceof Result; // true

Defined in

projects/utilities/packages/result/src/lib/Result.ts:1027

all()

static all<Entries>(this: void, results: Entries): Result<UnwrapOkArray<Entries>, UnwrapErrArray<Entries>[number], boolean>

Creates an Ok that is the combination of all collected Ok values as an array, or the first Err encountered.

Type Parameters

Type Parameter
`Entries` extends readonly `Any`[]

Parameters

Parameter	Type	Description
`this`	`void`	-
`results`	`Entries`	An array of Results.

Returns

Result<UnwrapOkArray<Entries>, UnwrapErrArray<Entries>[number], boolean>

A new Result.

Defined in

projects/utilities/packages/result/src/lib/Result.ts:1109

any()

static any<Entries>(this: void, results: Entries): Result<UnwrapOk<Entries[number]>, UnwrapErrArray<Entries>, boolean>

Returns the first encountered Ok, or an Err that is the combination of all collected error values.

Type Parameters

Type Parameter
`Entries` extends readonly `Any`[]

Parameters

Parameter	Type	Description
`this`	`void`	-
`results`	`Entries`	An array of Results.

Returns

Result<UnwrapOk<Entries[number]>, UnwrapErrArray<Entries>, boolean>

A new Result.

Defined in

projects/utilities/packages/result/src/lib/Result.ts:1130

err()

static err<E, T>(this: void, value?: E): Err<E, T>

Type Parameters

Type Parameter	Default type
`E`	`undefined`
`T`	`any`

Parameters

Parameter	Type
`this`	`void`
`value`?	`E`

Returns

Err<E, T>

Defined in

projects/utilities/packages/result/src/lib/Result.ts:1005

from()

static from<T, E>(this: void, op: ResultResolvable<T, E, boolean> | () => ResultResolvable<T, E, boolean>): Result<T, E, boolean>

Creates a Result out of a callback.

Type Parameters

Type Parameter	Default type
`T`	-
`E`	`unknown`

Parameters

Parameter	Type
`this`	`void`
`op`	`ResultResolvable`<`T`, `E`, `boolean`> \| () => `ResultResolvable`<`T`, `E`, `boolean`>

Returns

Result<T, E, boolean>

Typeparam

T The result's type.

Typeparam

E The error's type.

Defined in

projects/utilities/packages/result/src/lib/Result.ts:1076

fromAsync()

static fromAsync<T, E>(this: void, op: Awaitable<ResultResolvable<T, E, boolean>> | () => Awaitable<ResultResolvable<T, E, boolean>>): Promise<Result<T, E, boolean>>

Creates a Result out of a promise or async callback.

Type Parameters

Type Parameter	Default type
`T`	-
`E`	`unknown`

Parameters

Parameter	Type
`this`	`void`
`op`	`Awaitable`<`ResultResolvable`<`T`, `E`, `boolean`>> \| () => `Awaitable`<`ResultResolvable`<`T`, `E`, `boolean`>>

Returns

Promise<Result<T, E, boolean>>

Typeparam

T The result's type.

Typeparam

E The error's type.

Defined in

projects/utilities/packages/result/src/lib/Result.ts:1090

is()

static is(instance: unknown): instance is Any

Parameters

Parameter	Type	Description
`instance`	`unknown`	The instance to check.

Returns

instance is Any

true if the instance is a Result or a Result-like object, false otherwise.

Deprecated

Use Result.isResult instead.

Checks if the instance object is an instance of Result, or if it is a Result-like object.

Example

import { Result } from '@sapphire/result';
const { ok } = require('@sapphire/result');

Result.isResult(ok(2)); // true

Defined in

projects/utilities/packages/result/src/lib/Result.ts:1047

isResult()

static isResult(instance: unknown): instance is Any

Checks if the instance object is an instance of Result, or if it is a Result-like object.

Parameters

Parameter	Type	Description
`instance`	`unknown`	The instance to check.

Returns

instance is Any

true if the instance is a Result or a Result-like object, false otherwise.

Example

import { Result } from '@sapphire/result';
const { ok } = require('@sapphire/result');

Result.isResult(ok(2)); // true

Defined in

projects/utilities/packages/result/src/lib/Result.ts:1065

ok()

static ok<T, E>(this: void, value?: T): Ok<T, E>

Type Parameters

Type Parameter	Default type
`T`	`undefined`
`E`	`any`

Parameters

Parameter	Type
`this`	`void`
`value`?	`T`

Returns

Ok<T, E>

Defined in

projects/utilities/packages/result/src/lib/Result.ts:998

Typeparam​

Typeparam​

See​

Type Parameters​

Constructors​

new Result()​

Parameters​

Returns​

Defined in​

Properties​

__STATUS__​

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[SuccessProperty]​

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[ValueProperty]​

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Methods​

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contains()​

contains(this, value)​

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contains(this, value)​

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containsErr()​

containsErr(this, error)​

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containsErr(this, error)​

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Defined in

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Accessors

[toStringTag]

Get Signature

Returns

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Methods

[iterator]()

Returns

Examples

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and()

Type Parameters

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andThen()

Type Parameters

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Defined in

contains()

contains(this, value)

Type Parameters

Parameters

Returns

Examples

See

Defined in

contains(this, value)

Parameters

Returns

Defined in

containsErr()

containsErr(this, error)

Parameters

Returns

Examples

See

Defined in

containsErr(this, error)

Type Parameters

Parameters

Returns

Defined in

eq()

Type Parameters

Parameters

Returns

See

Defined in

err()

Returns

Examples

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Defined in

expect()

Parameters

Returns

Examples