Skip to main content

Class: None

@sapphire/result.None

Implements

Constructors

constructor

new None()

Methods

[iterator]

[iterator](): Generator<never, any, unknown>

Returns an iterator over the possibly contained value.

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

Example

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

Example

const x = none;
for (const value of x) {
console.log(value);
}
// Doesn't log

See

Returns

Generator<never, any, unknown>

Implementation of

IOption.[iterator]

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:164


and

and(option): None

Returns None if the option is None, otherwise returns option.

Example

const x: Option<number> = some(2);
const y: Option<string> = none;
assert.equal(x.and(y), none);

Example

const x: Option<number> = none;
const y: Option<string> = some('foo');
assert.equal(x.and(y), none);

Example

const x: Option<number> = some(2);
const y: Option<string> = some('foo');
assert.equal(x.and(y), some('foo'));

Example

const x: Option<number> = none;
const y: Option<string> = none;
assert.equal(x.and(y), none);

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.and

Parameters

NameTypeDescription
optionOption<any>The option.

Returns

None

Implementation of

IOption.and

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:85


andThen

andThen(cb): None

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.

Example

function fractionOf4(value: number) {
return value === 0 ? none : some(4 / value);
}

assert.equal(some(2).andThen(fractionOf4), some(4));
assert.equal(some(0).andThen(fractionOf4), none);
assert.equal(none.andThen(fractionOf4), none);

See

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

Parameters

NameTypeDescription
cb(value: never) => Option<any>The predicate.

Returns

None

Implementation of

IOption.andThen

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:90


contains

contains(value?): false

Returns true if the option is a Some value containing the given value.

Example

const x: Option<number> = some(2);
assert.equal(x.contains(2), true);

Example

const x: Option<number> = some(3);
assert.equal(x.contains(2), false);

Example

const x: Option<number> = none;
assert.equal(x.contains(2), false);

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.contains

Parameters

NameTypeDescription
value?anyThe value to compare.

Returns

false

Implementation of

IOption.contains

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:115


eq

eq(other): true

Checks whether or not other equals with self.

See

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

Parameters

NameTypeDescription
otherNoneThe other option to compare.

Returns

true

Implementation of

IOption.eq

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:146

eq(other): false

Parameters

NameType
otherSome<any>

Returns

false

Implementation of

IOption.eq

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:147

eq(other): boolean

Parameters

NameType
otherOption<any>

Returns

boolean

Implementation of

IOption.eq

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:148


expect

expect(message): never

Returns the contained Some value.

Example

const x: Option<string> = some(2);
assert.equal(x.expect('Whoops!'), 2);

Example

const x: Option<string> = none;
assert.throws(() => x.expect('Whoops!'), {
name: 'OptionError',
message: 'Whoops'
});

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.expect

Parameters

NameTypeDescription
messagestringThe message for the error. If the value is an Err, it throws an OptionError with the given message.

Returns

never

Implementation of

IOption.expect

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:23


filter

filter(predicate): None

Returns None if the option is None, otherwise calls predicate with the wrapped value and returns:

  • Some(t) if predicate returns true (where t is the wrapped value), and
  • None if predicate returns false.

Example

function isEven(value: number) {
return n % 2 === 0;
}

assert.equal(none.filter(isEven), none);
assert.equal(some(3).filter(isEven), none);
assert.equal(some(4).filter(isEven), some(4));

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.filter

Parameters

NameTypeDescription
predicate(value: never) => booleanThe predicate.

Returns

None

Implementation of

IOption.filter

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:110


flatten

flatten(): None

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

Example

const x: Option<Option<number>> = some(some(6));
assert.equal(x.flatten(), some(6));

Example

const x: Option<Option<number>> = some(none);
assert.equal(x.flatten(), none);

Example

const x: Option<Option<number>> = none;
assert.equal(x.flatten(), none);

See

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

Returns

None

Implementation of

IOption.flatten

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:138


inspect

inspect(cb?): None

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

Seealso

inspectAsync for the awaitable version.

Example

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

Example

none.inspect(console.log);
// Doesn't log

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.inspect

Parameters

NameTypeDescription
cb?(value: never) => voidThe predicate.

Returns

None

Implementation of

IOption.inspect

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:63


inspectAsync

inspectAsync(cb?): Promise<None>

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

Seealso

inspect for the sync version.

Example

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

Example

await none.inspectAsync(console.log);
// Doesn't log

Note

This is an extension not supported in Rust

Parameters

NameTypeDescription
cb?(value: never) => unknownThe predicate.

Returns

Promise<None>

Implementation of

IOption.inspectAsync

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:68


intoPromise

intoPromise(): Promise<None>

Returns a Promise object with the awaited value (if Some).

Example

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

Note

This is an extension not supported in Rust

Returns

Promise<None>

Implementation of

IOption.intoPromise

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:142


isNone

isNone(): this is None

Returns true if the option is a None value.

Example

const x: Option<number> = some(2);
assert.equal(x.isNone(), false);

Example

const x: Option<number> = none;
assert.equal(x.isNone(), true);

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.is_none

Returns

this is None

Implementation of

IOption.isNone

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:19


isSome

isSome(): false

Returns true if the option is a Some value.

Example

const x: Option<number> = some(2);
assert.equal(x.isSome(), true);

Example

const x: Option<number> = none;
assert.equal(x.isSome(), false);

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.is_some

Returns

false

Implementation of

IOption.isSome

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:10


isSomeAnd

isSomeAnd(cb?): false

Returns true if the option is a Some and the value inside of it matches a predicate.

Example

const x: Option<number> = some(2);
assert.equal(x.isSomeAnd((x) => x > 1), true);

Example

const x: Option<number> = some(0);
assert.equal(x.isSomeAnd((x) => x > 1), false);

Example

const x: Option<number> = none;
assert.equal(x.isSomeAnd((x) => x > 1), false);

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.is_some_and

Parameters

NameTypeDescription
cb?(value: never) => booleanThe predicate.

Returns

false

Implementation of

IOption.isSomeAnd

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:14


iter

iter(): Generator<never, any, unknown>

Returns an iterator over the possibly contained value.

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

Example

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

Example

const x = none;
for (const value of x) {
console.log(value);
}
// Doesn't log

See

Returns

Generator<never, any, unknown>

Implementation of

IOption.iter

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:81


map

map(cb): None

Maps an Option<T> to Option<U> by applying a function to a contained value.

Example

const maybeSomeString = some('Hello, world!');
const maybeSomeLength = maybeSomeString.map((value) => value.length);

assert.equal(maybeSomeLength, some(13));

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.map

Parameters

NameTypeDescription
cb(value: never) => anyThe predicate.

Returns

None

Implementation of

IOption.map

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:39


mapInto

mapInto(cb): None

Maps a Some<T> to the returned Option<U> by applying a function to a contained value, leaving None untouched.

Example

const input: Option<string> = some('Hello, world!');
const result = input.mapInto((value) => some(value.length));

assert.equal(result, some(13));

Example

const input: Option<string> = none;
const result = input.mapInto((value) => some(value.length));

assert.equal(result, none);

Note

This is an extension not supported in Rust

Parameters

NameTypeDescription
cb(value: never) => Option<any>The predicate.

Returns

None

Implementation of

IOption.mapInto

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:44


mapNoneInto

mapNoneInto<R>(cb): R

Maps a None to the returned Option<U> by applying a function to a contained value, leaving Some<T> untouched.

Example

const input: Option<string> = some('Hello, world!');
const result = input.mapNoneInto(() => some(13));

assert.equal(result, some('Hello, world!'));

Example

const input: Option<string> = none;
const result = input.mapNoneInto(() => some(13));

assert.equal(result, some(13));

Note

This is an extension not supported in Rust

Type parameters

NameType
Rextends Option<any>

Parameters

NameTypeDescription
cb() => RThe predicate.

Returns

R

Implementation of

IOption.mapNoneInto

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:59


mapOr

mapOr<R>(defaultValue, cb?): R

Returns the provided default result (if none), or applies a function to the contained value (if any).

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.

Example

const x: Option<string> = some('hello');
assert.equal(x.mapOr(42, (value) => value.length), 5);

Example

const x: Option<string> = none;
assert.equal(x.mapOr(42, (value) => value.length), 42);

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.map_or

Type parameters

Name
R

Parameters

NameTypeDescription
defaultValueRThe default value.
cb?(value: never) => RThe predicate.

Returns

R

Implementation of

IOption.mapOr

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:49


mapOrElse

mapOrElse<R>(defaultValue, cb?): R

Computes a default function result (if none), or applies a different function to the contained value (if any).

Example

const x: Option<string> = some('hello');
assert.equal(x.mapOrElse(() => 42, (value) => value.length), 5);

Example

const x: Option<string> = none;
assert.equal(x.mapOrElse(() => 42, (value) => value.length), 42);

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.map_or_else

Type parameters

Name
R

Parameters

NameTypeDescription
defaultValue() => RThe default value.
cb?(value: never) => RThe predicate.

Returns

R

Implementation of

IOption.mapOrElse

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:54


match

match<SomeValue, NoneValue>(branches): NoneValue

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

Example

const option = some(4).match({
some: (v) => v,
none: () => 0
});
assert.equal(option, 4);

Example

const option = none.match({
some: (v) => v,
none: () => 0
});
assert.equal(option, 0);

Type parameters

Name
SomeValue
NoneValue

Parameters

NameTypeDescription
branchesObjectThe branches to match.
branches.none() => NoneValue-
branches.some(value: never) => SomeValue-

Returns

NoneValue

Implementation of

IOption.match

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:160


ne

ne(other): false

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

See

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

Parameters

NameTypeDescription
otherNoneThe other option to compare.

Returns

false

Implementation of

IOption.ne

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:153

ne(other): true

Parameters

NameType
otherSome<any>

Returns

true

Implementation of

IOption.ne

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:154

ne(other): boolean

Parameters

NameType
otherOption<any>

Returns

boolean

Implementation of

IOption.ne

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:155


okOr

okOr<E>(error): Err<E>

Transforms the Option<T> into a Result<T, E>, mapping Some(v) to Ok(v) and None to Err(err).

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

Example

const x: Option<string> = some('hello');
assert.equal(x.okOr(0), ok('hello'));

Example

const x: Option<string> = none;
assert.equal(x.okOr(0), err(0));

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.ok_or

Type parameters

Name
E

Parameters

NameTypeDescription
errorEThe error to be used.

Returns

Err<E>

Implementation of

IOption.okOr

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:73


okOrElse

okOrElse<E>(cb): Err<E>

Transforms the Option<T> into a Result<T, E>, mapping Some(v) to Ok(v) and None to Err(err()).

Example

const x: Option<string> = some('hello');
assert.equal(x.okOrElse(() => 0), ok('hello'));

Example

const x: Option<string> = none;
assert.equal(x.okOrElse(() => 0), err(0));

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.ok_or_else

Type parameters

Name
E

Parameters

NameTypeDescription
cb() => EThe error to be used.

Returns

Err<E>

Implementation of

IOption.okOrElse

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:77


or

or<R>(option): R

Returns the option if it contains a value, otherwise returns option.

Example

const x: Option<number> = some(2);
const y: Option<number> = none;
assert.equal(x.or(y), some(2));

Example

const x: Option<number> = none;
const y: Option<number> = some(100);
assert.equal(x.or(y), some(100));

Example

const x: Option<number> = some(2);
const y: Option<number> = some(100);
assert.equal(x.or(y), some(2));

Example

const x: Option<number> = none;
const y: Option<number> = none;
assert.equal(x.or(y), none);

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.or

Type parameters

NameType
Rextends Option<any>

Parameters

NameTypeDescription
optionRThe option.

Returns

R

Implementation of

IOption.or

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:95


orElse

orElse<R>(cb): R

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.

Example

const nobody = (): Option<string> => none;
const vikings = (): Option<string> => some('vikings');

assert.equal(some('barbarians').orElse(vikings), some('barbarians'));
assert.equal(none.orElse(vikings), some('vikings'));
assert.equal(none.orElse(nobody), none);

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.or_else

Type parameters

NameType
Rextends Option<any>

Parameters

NameTypeDescription
cb() => RThe predicate.

Returns

R

Implementation of

IOption.orElse

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:99


transpose

transpose(): Ok<None>

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

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

Example

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

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.transpose

Returns

Ok<None>

Implementation of

IOption.transpose

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:134


unwrap

unwrap(): never

Returns the contained Some value.

If the value is an Err, it throws an OptionError with the message.

Seealso

unwrapOr

Seealso

unwrapOrElse

Example

const x: Option<string> = some(2);
assert.equal(x.unwrap(), 2);

Example

const x: Option<string> = none;
assert.throws(() => x.unwrap(), {
name: 'OptionError',
message: 'Unwrap failed'
});

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.unwrap

Returns

never

Implementation of

IOption.unwrap

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:27


unwrapOr

unwrapOr<R>(defaultValue): R

Returns the contained Some value or a 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.

Example

assert.equal(some(2).unwrapOr(0), 2);

Example

assert.equal(none.unwrapOr(0), 0);

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.unwrap_or

Type parameters

Name
R

Parameters

NameType
defaultValueR

Returns

R

Implementation of

IOption.unwrapOr

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:31


unwrapOrElse

unwrapOrElse<R>(cb): R

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

Example

assert.equal(some(2).unwrapOrElse(() => 0), 2);

Example

assert.equal(none.unwrapOrElse(() => 0), 0);

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.unwrap_or_else

Type parameters

Name
R

Parameters

NameType
cb() => R

Returns

R

Implementation of

IOption.unwrapOrElse

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:35


unzip

unzip(): [None, None]

Unzips an option containing a tuple of two options.

If self is Some((a, b)) this method returns [Some(a), Some(b)]. Otherwise, [None, None] is returned.

Example

const x: Option<[number, string]> = some([1, 'hi']);
assert.equal(x.unzip(), [some(1), some('hi')]);

Example

const x: Option<[number, string]> = none;
assert.equal(x.unzip(), [none, none]);

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.unzip

Returns

[None, None]

Implementation of

IOption.unzip

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:130


xor

xor<T>(option): None

Returns Some if exactly one of self or option is Some, otherwise returns None.

Example

const x: Option<number> = some(2);
const y: Option<number> = none;
assert.equal(x.xor(y), some(2));

Example

const x: Option<number> = none;
const y: Option<number> = some(2);
assert.equal(x.xor(y), some(2));

Example

const x: Option<number> = some(2);
const y: Option<number> = some(2);
assert.equal(x.xor(y), none);

Example

const x: Option<number> = none;
const y: Option<number> = none;
assert.equal(x.xor(y), none);

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.xor

Type parameters

Name
T

Parameters

NameTypeDescription
optionNoneThe option to compare.

Returns

None

Implementation of

IOption.xor

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:103

xor<T>(option): Some<T>

Type parameters

Name
T

Parameters

NameType
optionSome<T>

Returns

Some<T>

Implementation of

IOption.xor

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:104

xor<T>(option): None | Some<T>

Type parameters

Name
T

Parameters

NameType
optionOption<T>

Returns

None | Some<T>

Implementation of

IOption.xor

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:105


zip

zip(other): None

Zips self with another Option.

If self is Some(s) and other is Some(o), this method returns Some([s, o]). Otherwise, None is returned.

Example

const x = some(1);
const y = some('hi');
const z = none;

assert.equal(x.zip(y), some([1, 'hi']));
assert.equal(x.zip(z), none);

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.zip

Parameters

NameTypeDescription
otherOption<any>The option to zip self with.

Returns

None

Implementation of

IOption.zip

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:120


zipWith

zipWith(other, f): None

Zips self and another Option with function f.

If self is Some(s) and other is Some(o), this method returns Some(f(s, o)). Otherwise, None is returned.

Example

class Point {
public readonly x: number;
public readonly y: number;

public constructor(x: number, y: number) {
this.x = x;
this.y = y;
}
}

const x = some(17.5);
const y = some(42.7);

assert.equal(x.zipWith(y, (s, o) => new Point(s, o)), some(new Point(17.5, 42.7)));
assert.equal(x.zipWith(none, (s, o) => new Point(s, o)), none);

See

https://doc.rust-lang.org/std/option/enum.Option.html#method.zip_with

Parameters

NameTypeDescription
otherOption<any>The option to zip self with.
f(s: never, o: never) => anyThe function that computes the returned value.

Returns

None

Implementation of

IOption.zipWith

Defined in

projects/utilities/packages/result/src/lib/Option/None.ts:125