Globals / Managed

Class: Managed<A1, E1, R1>

Is a special data structures that encapsulates the acquisition and the release of a resource.

Example:

import * as fs from 'fs'
import {QIO, Managed} from '@qio/core'

// Utility Functions
const fsOpen = (name: string) => QIO.node(cb => fs.open(name, cb))
const fsClose = (fd: number) => QIO.try(() => fs.close(fd))
const fsWrite = (fd: number, text: string) => QIO.node((cb) => fs.write(fd, text, cb))

// Create a managed File Descriptor resource
const fdManaged = (name: string) => Managed.make(fsOpen(name), fsClose)

// Use the `fdManaged` to write the file.
fdManaged('./data.json').use(fd => fsWrite(fd, 'HI'))

In the above example as soon as the fsWrite is completed the file descriptor is automatically released.

Type parameters

Name	Default
`A1`	unknown
`E1`	never
`R1`	unknown

Hierarchy

Managed

Index

Methods

chain

▸ chain<A2, E2, R2>(fn: (a: A1) => Managed<A2, E2, R2>): Managed<A2, E1 | E2, R1 & R2>

Defined in packages/core/lib/main/Managed.ts:62

Type parameters:

Name
`A2`
`E2`
`R2`

Parameters:

Name	Type
`fn`	(a: A1) => Managed<A2, E2, R2>

Returns: Managed<A2, E1 | E2, R1 & R2>

map

▸ map<A2>(fn: (a: A1) => A2): Managed<A2, E1, R1>

Defined in packages/core/lib/main/Managed.ts:79

Type parameters:

Name
`A2`

Parameters:

Name	Type
`fn`	(a: A1) => A2

Returns: Managed<A2, E1, R1>

use

▸ use<A2, E2, R2>(fn: (a: A1) => QIO<A2, E2, R2>): QIO<A2, E1 | E2, R1 & R2>

Defined in packages/core/lib/main/Managed.ts:87

Type parameters:

Name
`A2`
`E2`
`R2`

Parameters:

Name	Type
`fn`	(a: A1) => QIO<A2, E2, R2>

Returns: QIO<A2, E1 | E2, R1 & R2>

use_

▸ use_<A2, E2, R2>(io: QIO<A2, E2, R2>): QIO<A2, E1 | E2, R1 & R2>

Defined in packages/core/lib/main/Managed.ts:93

Type parameters:

Name
`A2`
`E2`
`R2`

Parameters:

Name	Type
`io`	QIO<A2, E2, R2>

Returns: QIO<A2, E1 | E2, R1 & R2>

zipWith

▸ zipWith<A2, E2, R2, X>(that: Managed<A2, E2, R2>, fn: (a1: A1, a2: A2) => X): Managed<X, E1 | E2, R1 & R2>

Defined in packages/core/lib/main/Managed.ts:97

Type parameters:

Name
`A2`
`E2`
`R2`
`X`

Parameters:

Name	Type
`that`	Managed<A2, E2, R2>
`fn`	(a1: A1, a2: A2) => X

Returns: Managed<X, E1 | E2, R1 & R2>

make

▸ Staticmake<A1, E1, R1, E2, R2>(acquire: QIO<A1, E1, R1>, release: (a: A1) => QIO<unknown, E2, R2>): Managed<A1, E1 | E2, R1 & R2>

Defined in packages/core/lib/main/Managed.ts:29

Type parameters:

Name
`A1`
`E1`
`R1`
`E2`
`R2`

Parameters:

Name	Type
`acquire`	QIO<A1, E1, R1>
`release`	(a: A1) => QIO<unknown, E2, R2>

Returns: Managed<A1, E1 | E2, R1 & R2>

of

▸ Staticof<A1, E1, R1>(reservation: QIO<Reservation<A1, E1, R1>, E1, R1>): Managed<A1, E1, R1>

Defined in packages/core/lib/main/Managed.ts:40

Type parameters:

Name
`A1`
`E1`
`R1`

Parameters:

Name	Type
`reservation`	QIO<Reservation<A1, E1, R1>, E1, R1>

Returns: Managed<A1, E1, R1>

zip

▸ Staticzip<A1, E1, R1>(managed: Array<Managed<A1, E1, R1>>): Managed<A1[], E1, R1>

Defined in packages/core/lib/main/Managed.ts:46

Type parameters:

Name
`A1`
`E1`
`R1`

Parameters:

Name	Type
`managed`	Array<Managed<A1, E1, R1>>

Returns: Managed<A1[], E1, R1>