Class: Err<E>

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
`E`

Implements

IResult<any, E>

Constructors

new Err()

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

Parameters

Parameter	Type
`error`	`E`

Returns

Err<E>

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:12

Properties

error

private readonly error: E

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:10

Methods

`[iterator]`()

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

Returns an iterator over the possibly contained value.

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

Returns

Generator<never, any, unknown>

Implementation of

IResult . [iterator]

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:182

and()

and(result?: Result<any, E>): this

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

Parameters

Parameter	Type	Description
`result`?	`Result`<`any`, `E`>	The result to check.

Returns

this

Implementation of

IResult . and

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

Source

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

andThen()

andThen(cb?: (value: never) => Result<any, E>): this

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`?	(`value`: `never`) => `Result`<`any`, `E`>	The predicate.

Returns

this

Implementation of

IResult . andThen

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:128

contains()

contains(value?: any): false

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

Parameters

Parameter	Type	Description
`value`?	`any`	The value to compare.

Returns

false

Implementation of

IResult . contains

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:141

containsErr()

containsErr(error: E): boolean

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

Parameters

Parameter	Type	Description
`error`	`E`	The error to compare.

Returns

boolean

Implementation of

IResult . containsErr

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

Source

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

eq()

eq(other)

eq(other: Ok<any>): false

Checks whether or not other equals with self.

Parameters

Parameter	Type	Description
`other`	`Ok`<`any`>	The other result to compare.

Returns

false

eq(other)

eq(other: Result<any, E>): boolean

Parameters

Parameter	Type
`other`	`Result`<`any`, `E`>

Returns

boolean

Implementation of

IResult.eq

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:167

err()

err(): Some<E>

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

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

Returns

Some<E>

Implementation of

IResult . err

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:37

expect()

expect(message: string): 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

never

Implementation of

IResult . expect

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:93

expectErr()

expectErr(message?: string): 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

E

Implementation of

IResult . expectErr

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:97

flatten()

flatten(): this

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

Returns

this

Implementation of

IResult . flatten

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:154

inspect()

inspect(cb?: (value: never) => void): this

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

Parameters

Parameter	Type	Description
`cb`?	(`value`: `never`) => `void`	The predicate.

Returns

this

Implementation of

IResult . inspect

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:69

inspectAsync()

inspectAsync(cb?: (value: never) => unknown): Promise <Err<E>>

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

Parameters

Parameter	Type	Description
`cb`?	(`value`: `never`) => `unknown`	The predicate.

Returns

Promise <Err<E>>

Implementation of

IResult . inspectAsync

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

Source

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

inspectErr()

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

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

Parameters

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

Returns

this

Implementation of

IResult . inspectErr

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:79

inspectErrAsync()

inspectErrAsync(cb: (error: E) => unknown): Promise <Err<E>>

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 <Err<E>>

Implementation of

IResult . inspectErrAsync

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:84

intoOkOrErr()

intoOkOrErr(): E

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

Returns

E

Implementation of

IResult . intoOkOrErr

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:158

intoPromise()

intoPromise(): Promise <Err <Awaited<E>>>

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

Returns

Promise <Err <Awaited<E>>>

Implementation of

IResult . intoPromise

Example

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

Note

This is an extension not supported in Rust

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:162

isErr()

isErr(): this is Err<E>

Returns true if the result is Err.

Returns

this is Err<E>

Implementation of

IResult . isErr

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

Source

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

isErrAnd()

isErrAnd(cb: (error: E) => boolean): boolean

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

Parameters

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

Returns

boolean

Implementation of

IResult . isErrAnd

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:29

isOk()

isOk(): false

Returns true if the result is Ok.

Returns

false

Implementation of

IResult . isOk

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:16

isOkAnd()

isOkAnd(cb?: (value: never) => boolean): false

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

Parameters

Parameter	Type
`cb`?	(`value`: `never`) => `boolean`

Returns

false

Implementation of

IResult . isOkAnd

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:20

iter()

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

Returns an iterator over the possibly contained value.

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

Returns

Generator<never, any, unknown>

Implementation of

IResult . iter

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:89

map()

map(cb?: (value: never) => unknown): this

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

Parameters

Parameter	Type	Description
`cb`?	(`value`: `never`) => `unknown`	The predicate.

Returns

this

Implementation of

IResult . map

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:41

mapErr()

mapErr<F>(cb: (error: E) => F): Err<F>

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
`F`

Parameters

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

Returns

Err<F>

Implementation of

IResult . mapErr

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:61

mapErrInto()

mapErrInto<R>(cb: (error: E) => R): R

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
`R` extends `Result`<`any`, `any`>

Parameters

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

Returns

R

Implementation of

IResult . mapErrInto

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:65

mapInto()

mapInto(cb: (value: never) => Result<any, any>): this

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.

Parameters

Parameter	Type	Description
`cb`	(`value`: `never`) => `Result`<`any`, `any`>	The predicate.

Returns

this

Implementation of

IResult . mapInto

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:46

mapOr()

mapOr<U>(defaultValue: U, cb?: (value: never) => U): U

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
`U`

Parameters

Parameter	Type	Description
`defaultValue`	`U`	The default value to use.
`cb`?	(`value`: `never`) => `U`	The predicate.

Returns

U

Implementation of

IResult . mapOr

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:51

mapOrElse()

mapOrElse<U>(op: (error: E) => U, cb?: (value: never) => U): U

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
`U`

Parameters

Parameter	Type	Description
`op`	(`error`: `E`) => `U`	The predicate that is run on `Err`.
`cb`?	(`value`: `never`) => `U`	The predicate that is run on `Ok`.

Returns

U

Implementation of

IResult . mapOrElse

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:56

match()

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

ErrValue

Implementation of

IResult . match

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);

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:178

ne()

ne(other)

ne(other: Ok<any>): true

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

Parameters

Parameter	Type	Description
`other`	`Ok`<`any`>	The other result to compare.

Returns

true

Implementation of

IResult . ne

See

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:172

ne(other)

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

Parameters

Parameter	Type
`other`	`Result`<`any`, `E`>

Returns

boolean

Implementation of

IResult.ne

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:173

ok()

ok(): None

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

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

Returns

None

Implementation of

IResult . ok

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:33

or()

or<R>(result: R): R

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
`R` extends `Result`<`any`, `any`>

Parameters

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

Returns

R

Implementation of

IResult . or

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:133

orElse()

orElse<R>(cb: (error: E) => R): R

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
`R` extends `Result`<`any`, `any`>

Parameters

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

Returns

R

Implementation of

IResult . orElse

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:137

transpose()

transpose(): Some <Err<E>>

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)).

Returns

Some <Err<E>>

Implementation of

IResult . transpose

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:150

unwrap()

unwrap(): 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

never

Implementation of

IResult . unwrap

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:102

unwrapErr()

unwrapErr(): 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

E

Implementation of

IResult . unwrapErr

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:106

unwrapOr()

unwrapOr<T>(defaultValue: T): T

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
`T`

Parameters

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

Returns

T

Implementation of

IResult . unwrapOr

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:110

unwrapOrElse()

unwrapOrElse<T>(op: (error: E) => T): T

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

Type parameters

Type parameter
`T`

Parameters

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

Returns

T

Implementation of

IResult . unwrapOrElse

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

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:114

unwrapRaw()

unwrapRaw(): never

Returns the contained Ok value.

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

Returns

never

Implementation of

IResult . unwrapRaw

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'
});

Source

projects/utilities/packages/result/src/lib/Result/Err.ts:118

Class: Err<E>

Typeparam​

Typeparam​

See​

Type parameters​

Implements​

Constructors​

new Err()​

Parameters​

Returns​

Source​

Properties​

error​

Source​

Methods​

[iterator]()​

Returns​

Implementation of​

Examples​

See​

Source​

and()​

Parameters​

Returns​

Implementation of​

Examples​

See​

Source​

andThen()​

Parameters​

Returns​

Implementation of​

Example​

See​

Source​

contains()​

Parameters​

Returns​

Implementation of​

Examples​

See​

Source​

containsErr()​

Parameters​

Returns​

Implementation of​

Examples​

See​

Source​

eq()​

eq(other)​

Parameters​

Returns​

Implementation of​

See​

Source​

eq(other)​

Parameters​

Returns​

Implementation of​

Source​

err()​

Returns​

Implementation of​

Examples​

See​

Source​

expect()​

Parameters​

Returns​

Implementation of​

Examples​

See​

Source​

expectErr()​

Parameters​

Returns​

Implementation of​

Examples​

See​

Typeparam

Typeparam

See

Type parameters

Implements

Constructors

new Err()

Parameters

Returns

Source

Properties

error

Source

Methods

`[iterator]`()

Returns

Implementation of

Examples

See

Source

and()

Parameters

Returns

Implementation of

Examples

See

Source

andThen()

Parameters

Returns

Implementation of

Example

See

Source

contains()

Parameters

Returns

Implementation of

Examples

See

Source

containsErr()

Parameters

Returns

Implementation of

Examples

See

Source

eq()

eq(other)

Parameters

Returns

Implementation of

See

Source

eq(other)

Parameters

Returns

Implementation of

Source

err()

Returns

Implementation of

Examples

See

Source

expect()

Parameters

Returns

Implementation of

Examples

See

Source

expectErr()

Parameters

Returns

Implementation of

Examples

See

Source