IOOption overview

Utility functions to accommodate fp-ts/IOOption.

Added in v0.16.0

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Table of contents

• 2 Typeclass Methods
  • pass
• 3 Functions
  • unsafeExpect
  • unsafeUnwrap

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2 Typeclass Methods

pass

Convenient alias for IOO.of(undefined).

Signature

export declare const pass: IOOption<void>

pass :: IOOption void

Example

import { flow, pipe, constant } from 'fp-ts/function'
import * as Fn from 'fp-ts-std/Function'
import * as O from 'fp-ts/Option'
import Option = O.Option
import * as IOO from 'fp-ts/IOOption'
import IOOption = IOO.IOOption
import { pass } from 'fp-ts-std/IOOption'
import { log } from 'fp-ts/Console'

const mcount: Option<number> = O.some(123)
const tryLog: <A>(x: A) => IOOption<void> = flow(log, IOO.fromIO)

const logCount: IOOption<void> = pipe(mcount, O.match(constant(pass), tryLog))

Added in v0.17.0

3 Functions

unsafeExpect

Unwrap the value from within an IOOption, throwing msg if None.

Signature

export declare const unsafeExpect: (msg: string) => <A>(x: IOOption<A>) => A

unsafeExpect :: string -> IOOption a -> a

Example

import { unsafeExpect } from 'fp-ts-std/IOOption'
import * as IOO from 'fp-ts/IOOption'

assert.throws(() => unsafeExpect('foo')(IOO.none), Error('Unwrapped `None`', { cause: 'foo' }))

Added in v0.16.0

unsafeUnwrap

Unwrap the value from within an IOOption, throwing if None.

Signature

export declare const unsafeUnwrap: <A>(x: IOOption<A>) => A

unsafeUnwrap :: IOOption a -> a

Example

import { unsafeUnwrap } from 'fp-ts-std/IOOption'
import * as IOO from 'fp-ts/IOOption'

assert.strictEqual(unsafeUnwrap(IOO.some(5)), 5)

Added in v0.16.0