Class Optional<T>

Wrapper for a value that might or might not be present.

Type Parameters

T

Index

Methods

empty filter flatMap ifEmpty ifPresent isEmpty isPresent map of orCrash orElse orFail orGet

Methods

`Static`empty

empty<T>(): Optional<Exclude<T, undefined | null>>
Create an empty Optional instance
Type Parameters
- T
Returns Optional<Exclude<T, undefined | null>>
An empty Optional

filter

filter(filter: (value: T) => unknown): Optional<T>
Filter the value (if present)
Parameters
- filter: (value: T) => unknown
Returns Optional<T>

flatMap

flatMap<R>(map: (value: T) => Optional<R>): Optional<R>
Map the value (if present) and unwrap the resulting Optional
Type Parameters
- R
Parameters
- map: (value: T) => Optional<R>
Returns Optional<R>

ifEmpty

ifEmpty(action: () => void): this
Perform an action if the Optional does not contain a value
Parameters
- action: () => void
Returns this

ifPresent

ifPresent(action: (value: T) => void): this
Perform an action if the Optional contains a value
Parameters
- action: (value: T) => void
Returns this

isEmpty

isEmpty(): boolean
Check if the Optional is empty

Returns boolean

isPresent

isPresent(): this is Optional<T> & { get: () => T }
Check if the Optional contains a value

Returns this is Optional<T> & { get: () => T }

map

map<R>(map: (value: T) => R): Optional<R>
Map the value (if present)
Type Parameters
- R
Parameters
- map: (value: T) => R
Returns Optional<R>

`Static`of

of<T>(value: T): Optional<Exclude<T, undefined | null>>
Create an optional
Type Parameters
- T
Parameters
- value: T
Returns Optional<Exclude<T, undefined | null>>

orCrash

orCrash(message: string): T
Get the value (if present) or fail with a an internal error
Parameters
- message: string
Returns T

orElse

orElse<U>(fallbackValue: U): T | U
Get the value (if present) or return the specified default value otherwise
Type Parameters
- U
Parameters
- fallbackValue: U
Returns T | U

orFail

orFail(message: string): T
Get the value (if present) or fail with a user-friendly error message
Parameters
- message: string
Returns T

orGet

orGet<U>(get: () => U): T | U
Get the value (if present) or call the specified function and return its return value otherwise
Type Parameters
- U
Parameters
- get: () => U
Returns T | U