Calls mapper if the result is Ok, otherwise returns the Err value of self.
This function can be used for control flow based on Result values.
Returns the contained Ok value, if exists. Throws an error if not.
The thrown error's
[cause'](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/cause) is set to value contained in Err`.
If you know you're dealing with Ok and the compiler knows it too (because you tested
isOk() or isErr()) you should use value instead. While Ok's expect() and value will
both return the same value using value is preferable because it makes it clear that
there won't be an exception thrown on access.
the message to throw if no Ok value.
Maps a Result<T, E> to Result<U, E> by applying a function to a contained Ok value,
leaving an Err value untouched.
This function can be used to compose the results of two functions.
Maps a Result<T, E> to Result<U, E> by either converting T to U using mapper
(in case of Ok) or using the default_ value (in case of Err).
If default is a result of a function call consider using mapOrElse instead, it will
only evaluate the function when needed.
Maps a Result<T, E> to Result<U, E> by either converting T to U using mapper
(in case of Ok) or producing a default value using the default function (in case of
Err).
Returns Ok() if we have a value, otherwise returns other.
other is evaluated eagerly. If other is a result of a function
call try orElse() instead – it evaluates the parameter lazily.
Ok(1).or(Ok(2)) // => Ok(1)
Err('error here').or(Ok(2)) // => Ok(2)
Returns Ok() if we have a value, otherwise returns the result
of calling other().
other() is called only when needed and is passed the error value in a parameter.
Ok(1).orElse(() => Ok(2)) // => Ok(1)
Err('error').orElse(() => Ok(2)) // => Ok(2)
Returns the contained Ok value, but never throws.
Unlike unwrap(), this method doesn't throw and is only callable on an Ok
Therefore, it can be used instead of unwrap() as a maintainability safeguard
that will fail to compile if the error type of the Result is later changed to an error that can actually occur.
(this is the into_ok() in rust)
Creates an AsyncResult based on this Result.
Useful when you need to compose results with asynchronous code.
Returns the contained Ok value.
Because this function may throw, its use is generally discouraged.
Instead, prefer to handle the Err case explicitly.
If you know you're dealing with Ok and the compiler knows it too (because you tested
isOk() or isErr()) you should use value instead. While Ok's unwrap() and value will
both return the same value using value is preferable because it makes it clear that
there won't be an exception thrown on access.
Throws if the value is an Err, with a message provided by the Err's value and
[`cause'](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/cause)
set to the value.
Returns the contained Err value.
Because this function may throw, its use is generally discouraged.
Instead, prefer to handle the Ok case explicitly.
Throws if the value is an Ok, with a message provided by the Ok's value and
[`cause'](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/cause)
set to the value.
Readonly valueStatic Readonly EMPTY
Contains the success value