Interface: IOption<T>

Type Parameters

Type Parameter
`T`

Methods

[iterator]()

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

Returns an iterator over the possibly contained value.

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

Returns

Generator<T, any, unknown>

Examples

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

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

See

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:738

and()

and<U>(option: Option<U>): Option<U>

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

Type Parameters

Type Parameter
`U`

Parameters

Parameter	Type	Description
`option`	`Option`<`U`>	The option.

Returns

Option<U>

Examples

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

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

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

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:397

andThen()

andThen<U>(cb: (value: T) => Option<U>): Option<U>

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
`U`

Parameters

Parameter	Type	Description
`cb`	(`value`: `T`) => `Option`<`U`>	The predicate.

Returns

Option<U>

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:418

contains()

contains(value: T): boolean

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

Parameters

Parameter	Type	Description
`value`	`T`	The value to compare.

Returns

boolean

Examples

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

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

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

See

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:550

eq()

eq(other: Option<T>): boolean

Checks whether or not other equals with self.

Parameters

Parameter	Type	Description
`other`	`Option`<`T`>	The other option to compare.

Returns

boolean

See

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:680

expect()

expect(message: string): T

Returns the contained Some value.

Parameters

Parameter	Type	Description
`message`	`string`	The message for the error. If the value is an `Err`, it throws an OptionError with the given message.

Returns

T

Examples

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

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:89

filter()

filter(predicate: (value: T) => boolean): Option<T>

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.

Parameters

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

Returns

Option<T>

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:526

flatten()

flatten<IT>(this: Option<Option<IT>>): Option<IT>

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

Type Parameters

Type Parameter
`IT`

Parameters

Parameter	Type
`this`	`Option`<`Option`<`IT`>>

Returns

Option<IT>

Examples

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

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

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

See

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:659

inspect()

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

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

Parameters

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

Returns

this

Examples

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

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

See

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:276

inspectAsync()

inspectAsync(cb: (value: T) => Awaitable<void>): Promise<IOption<T>>

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

Parameters

Parameter	Type	Description
`cb`	(`value`: `T`) => `Awaitable`<`void`>	The predicate.

Returns

Promise<IOption<T>>

Examples

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

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

Note

This is an extension not supported in Rust

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:296

intoPromise()

intoPromise(): Promise<Option<Awaited<T>>>

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

Returns

Promise<Option<Awaited<T>>>

Example

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

Note

This is an extension not supported in Rust

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:672

isNone()

isNone(): this is None

Returns true if the option is a None value.

Returns

this is None

Examples

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

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

See

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:66

isSome()

isSome(): this is Some<T>

Returns true if the option is a Some value.

Returns

this is Some<T>

Examples

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

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

See

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:24

isSomeAnd()

isSomeAnd(cb: (value: T) => boolean): boolean

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

Parameters

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

Returns

boolean

Examples

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

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

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:48

iter()

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

Returns an iterator over the possibly contained value.

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

Returns

Generator<T, any, unknown>

Examples

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

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

See

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:364

map()

map<U>(cb: (value: T) => U): Option<U>

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

Type Parameters

Type Parameter
`U`

Parameters

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

Returns

Option<U>

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:165

mapInto()

mapInto<Inner>(cb: (value: T) => Option<Inner>): Option<Inner>

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

Type Parameters

Type Parameter
`Inner`

Parameters

Parameter	Type	Description
`cb`	(`value`: `T`) => `Option`<`Inner`>	The predicate.

Returns

Option<Inner>

Examples

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

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

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:189

mapNoneInto()

mapNoneInto<Inner>(cb: () => Option<Inner>): Option<T | Inner>

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

Type Parameters

Type Parameter
`Inner`

Parameters

Parameter	Type	Description
`cb`	() => `Option`<`Inner`>	The predicate.

Returns

Option<T | Inner>

Examples

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

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

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:256

mapOr()

mapOr<U>(defaultValue: U, cb: (value: T) => U): U

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.

Type Parameters

Type Parameter
`U`

Parameters

Parameter	Type	Description
`defaultValue`	`U`	The default value.
`cb`	(`value`: `T`) => `U`	The predicate.

Returns

U

Examples

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

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:212

mapOrElse()

mapOrElse<U>(defaultValue: () => U, cb: (value: T) => U): U

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

Type Parameters

Type Parameter
`U`

Parameters

Parameter	Type	Description
`defaultValue`	() => `U`	The default value.
`cb`	(`value`: `T`) => `U`	The predicate.

Returns

U

Examples

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

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:232

match()

match<SomeValue, NoneValue>(branches: object): SomeValue | NoneValue

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

Type Parameters

Type Parameter
`SomeValue`
`NoneValue`

Parameters

Parameter	Type	Description
`branches`	`object`	The branches to match.
`branches.none`	-
`branches.some`	-

Returns

SomeValue | NoneValue

Examples

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

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:711

ne()

ne(other: Option<T>): boolean

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

Parameters

Parameter	Type	Description
`other`	`Option`<`T`>	The other option 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/Option/IOption.ts:688

okOr()

okOr<E>(err: E): Result<T, 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.

Type Parameters

Type Parameter
`E`

Parameters

Parameter	Type	Description
`err`	`E`	The error to be used.

Returns

Result<T, E>

Examples

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

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:318

okOrElse()

okOrElse<E>(cb: () => E): Result<T, E>

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

Type Parameters

Type Parameter
`E`

Parameters

Parameter	Type	Description
`cb`	() => `E`	The error to be used.

Returns

Result<T, E>

Examples

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

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:337

or()

or(option: Option<T>): Option<T>

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

Parameters

Parameter	Type	Description
`option`	`Option`<`T`>	The option.

Returns

Option<T>

Examples

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

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

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

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:451

orElse()

orElse(cb: () => Option<T>): Option<T>

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.

Parameters

Parameter	Type	Description
`cb`	() => `Option`<`T`>	The predicate.

Returns

Option<T>

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:471

transpose()

transpose<IT, E>(this: Option<Result<IT, E>>): Result<Option<IT>, E>

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).

Type Parameters

Type Parameter
`IT`
`E`

Parameters

Parameter	Type
`this`	`Option`<`Result`<`IT`, `E`>>

Returns

Result<Option<IT>, 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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:636

unwrap()

unwrap(): T

Returns the contained Some value.

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

Returns

T

Examples

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

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:114

unwrapOr()

unwrapOr<V>(defaultValue: V): T | V

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.

Type Parameters

Type Parameter
`V`

Parameters

Parameter	Type
`defaultValue`	`V`

Returns

T | V

Examples

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

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

See

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:133

unwrapOrElse()

unwrapOrElse<V>(cb: () => V): T | V

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

Type Parameters

Type Parameter
`V`

Parameters

Parameter	Type
`cb`	() => `V`

Returns

T | V

Examples

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

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

See

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:149

unzip()

unzip<Inner, U>(this: Option<readonly [Inner, U]>): [Option<Inner>, Option<U>]

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.

Type Parameters

Type Parameter
`Inner`
`U`

Parameters

Parameter	Type
`this`	`Option`<readonly [`Inner`, `U`]>

Returns

[Option<Inner>, Option<U>]

Examples

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

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:620

xor()

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

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

Parameters

Parameter	Type	Description
`option`	`Option`<`T`>	The option to compare.

Returns

Option<T>

Examples

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

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

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

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:504

zip()

zip<U>(other: Option<U>): Option<[T, U]>

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.

Type Parameters

Type Parameter
`U`

Parameters

Parameter	Type	Description
`other`	`Option`<`U`>	The option to zip self with.

Returns

Option<[T, U]>

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:570

zipWith()

zipWith<U, R>(other: Option<U>, f: (s: T, o: U) => R): Option<R>

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.

Type Parameters

Type Parameter
`U`
`R`

Parameters

Parameter	Type	Description
`other`	`Option`<`U`>	The option to zip self with.
`f`	(`s`: `T`, `o`: `U`) => `R`	The function that computes the returned value.

Returns

Option<R>

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

Defined in

projects/utilities/packages/result/src/lib/Option/IOption.ts:600

Interface: IOption<T>

Type Parameters​

Methods​

[iterator]()​

Returns​

Examples​

See​

Defined in​

and()​

Type Parameters​

Parameters​

Returns​

Examples​

See​

Defined in​

andThen()​

Type Parameters​

Parameters​

Returns​

Example​

See​

Defined in​

contains()​

Parameters​

Returns​

Examples​

See​

Defined in​

eq()​

Parameters​

Returns​

See​

Defined in​

expect()​

Parameters​

Returns​

Examples​

See​

Defined in​

filter()​

Parameters​

Returns​

Example​

See​

Defined in​

flatten()​

Type Parameters​

Parameters​

Returns​

Examples​

See​

Defined in​

inspect()​

Parameters​

Returns​

Seealso​

Examples​

See​

Defined in​

inspectAsync()​

Parameters​

Returns​

Seealso​

Examples​

Note​

Defined in​

intoPromise()​

Returns​

Example​

Note​

Defined in​

isNone()​

Returns​

Examples​

See​

Defined in​

isSome()​

Returns​

Examples​

See​

Type Parameters

Methods

[iterator]()

Returns

Examples

See

Defined in

and()

Type Parameters

Parameters

Returns

Examples

See

Defined in

andThen()

Type Parameters

Parameters

Returns

Example

See

Defined in

contains()

Parameters

Returns

Examples

See

Defined in

eq()

Parameters

Returns

See

Defined in

expect()

Parameters

Returns

Examples

See

Defined in

filter()

Parameters

Returns

Example

See

Defined in

flatten()

Type Parameters

Parameters

Returns

Examples

See

Defined in

inspect()

Parameters

Returns

Seealso

Examples

See

Defined in

inspectAsync()

Parameters

Returns

Seealso

Examples

Note

Defined in

intoPromise()

Returns

Example

Note

Defined in

isNone()

Returns

Examples

See

Defined in

isSome()

Returns

Examples

See

Defined in