Err<S, F extends Object> class final

Error Result.

Returned when the result is an unexpected value

Implemented types

• Result<S, F>

Available extensions

• FlattenExtension
• InfallibleErrExtension
• InfallibleOkExtension
• NullResultExtension
• ResultFutureToFutureResultExtension
• ResultNullExtension
• ResultOptionExtension
• ResultToFutureResultExtension

Constructors

Err.new(F err)

Receives the F param as the error result.

const

Properties

err → F

final

hashCode → int

The hash code for this object.

no setter, override

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

and<S2>(Result<S2, F> other) → Result<S2, F>

Performs an "and" operation on the results. Returns the first result that is Err, otherwise if both are Ok, other Ok Result is returned.

override

andThen<W>(Result<W, F> fn(S ok)) → Result<W, F>

If Ok, Returns a new Result by passing the Ok value to the provided function.

override

andThenErr<W extends Object>(Result<S, W> fn(F error)) → Result<S, W>

/ If Err, Returns a new Result by passing the Err value to the provided function.

override

copy() → Err<S, F>

Performs a shallow copy of this result.

override

expect(String message) → S

Returns the ok value if Result is Ok. Throws a Panic if the Result is Err, with the provided message.

override

expectErr(String message) → F

Returns the err value if Result is Err. Throws a Panic if the Result is Ok, with the provided message.

override

flatten() → Result<S, F>

Available on Result<Result<S, F>, F>, provided by the FlattenExtension extension

Converts a Result of a Result into a single Result

inspect(void fn(S ok)) → Err<S, F>

If Ok, Calls the provided closure with the ok value, else does nothing.

override

inspectErr(void fn(F error)) → Err<S, F>

If Err, Calls the provided closure with the err value, else does nothing.

override

into<S2>() → Err<S2, F>

Changes the Ok type to S2. This is usually used when "this" is known to be an Err and you want to return to the calling function, but the returning function's S type is different from this S type.

intoErr() → F

Available on Result<Never, F>, provided by the InfallibleErrExtension extension

intoOk() → S

Available on Result<S, Never>, provided by the InfallibleOkExtension extension

intoUnchecked<S2>() → Err<S2, F>

Changes the Ok type to S2. See into for a safe implementation of intoUnchecked. This is usually used when "this" is known to be an Err and you want to return to the calling function, but the returning function's Ok type is different from this Ok type.

override

isErr() → bool

Returns true if the current result is an Err.

override

isErrAnd(bool fn(F)) → bool

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

override

isOk() → bool

Returns true if the current result is a Ok.

override

isOkAnd(bool fn(S)) → bool

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

override

iter() → RIterator<S>

Returns an iterable over the possibly contained value. The iterator yields one value if the result is Ok, otherwise none.

override

map<W>(W fn(S ok)) → Err<W, F>

Returns a new Result, mapping any Ok value using the given transformation.

override

mapErr<W extends Object>(W fn(F error)) → Err<S, W>

Returns a new Result, mapping any Err value using the given transformation.

override

mapOr<W>(W defaultValue, W fn(S ok)) → W

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

override

mapOrElse<W>(W defaultFn(F err), W fn(S ok)) → W

Evaluates the provided defaultFn (if Err), or applies a function to the contained value (if Ok).

override

match<W>({required W ok(S), required W err(F)}) → W

Returns the result of ok for the encapsulated value if this instance represents Ok or the result of err function for the encapsulated value if it is Err.

override

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

or<F2 extends Object>(Result<S, F2> other) → Result<S, F2>

Performs an "or" operation on the results. Returns the first Ok value, if neither are Ok, returns the other Err.

override

orElse<F2 extends Object>(Result<S, F2> fn(F)) → Result<S, F2>

Calls fn if the result is Err, otherwise returns the Ok value of this.

override

toFutureResult() → FutureResult<S, F>

Available on Result<S, F>, provided by the ResultToFutureResultExtension extension

Turns a Result into a FutureResult.

toFutureResult() → FutureResult<S, F>

Available on Result<Future<S>, F>, provided by the ResultFutureToFutureResultExtension extension

Turns a Result of a Future into a FutureResult.

toString() → String

A string representation of this object.

override

transpose() → Option<Result<S, F>>

Available on Result<Option<S?>, F>, provided by the ResultOptionExtension extension

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

transposeIn() → Result<S?, F>

Available on Result<S, F>?, provided by the NullResultExtension extension

transposes a nullable Result into a non-nullable Result. Note: transposeIn is named as such otherwise there is ambiguity if named the same as transposeOut (transpose).

transposeOut() → Result<S, F>?

Available on Result<S?, F>, provided by the ResultNullExtension extension

transposes a Result of a nullable type into a nullable Result. Note: transposeOut is named as such otherwise there is ambiguity if named the same as transposeIn (transpose).

unwrap() → S

Returns the ok value if Result is Ok. Throws a Panic if the Result is Err.

override

unwrapErr() → F

Returns the err value if Result is Err. Throws a Panic if the Result is Ok.

override

unwrapOr(S defaultValue) → S

Returns the encapsulated value if this instance represents Ok or the defaultValue if it is Err. Note: This should not be used to determine is Ok or is Err, since when the success type is nullable, a default value of null can be provided, which is ambiguous in meaning.

override

unwrapOrElse(S onError(F error)) → S

Returns the encapsulated value if this instance represents Ok or the result of onError function for the encapsulated a Err value. Note: This should not be used to determine is Ok or is Err, since when the success type is nullable, the value returned can be null, which is ambiguous in meaning.

override

unwrapOrNull() → S?

Returns the value of Ok or null. Note: This should not be used to determine is Ok or is Err, since when the success type is nullable, a null is ambiguous in meaning.

override

unwrapOrOption() → Option<S>

Converts a Result into an Option, returning Some if the Result is Ok, and _None if the Result is Err. Note: This should not be used to determine is Ok or is Err, since when the success type is nullable, a null is ambiguous in meaning.

override

Operators

operator ==(Object other) → bool

The equality operator.

override

operator [](_ResultEarlyReturnKey<F> op) → S

Functions an "Early Return Operator" when given an "Early Return key" "$". See Result.$ for more information.

override