Class Writer<S, A>

The Writer monad provides the ability to accumulate a secondary Story (S) value in addition to the return value (A) of a computation.

Type parameters

S

The array-based value of the Story (the accumulator).
A

The current return value of the computation.

Hierarchy

Writer

Implements

Eq<Writer<S, A>>
Monoid<A>
Monad<A>

Index

Properties

empty

Methods

Properties

empty

empty: A & object = empty<A>()

Methods

apply

apply<B>(func: Writer<S, function>): Writer<S, B>

- Defined in Writer.ts:69
Applies a function stored as the value of another Writer to the value of this Writer.

Type parameters
- B
Parameters
- func: Writer<S, function>
Returns Writer<S, B>

censor

censor(func: function): Writer<S, A>

- Defined in Writer.ts:59
Modify the Writer's story by applying a function.

Parameters
- func: function
  - - (s: S[]): S[]
    - Parameters
      - s: S[]
      Returns S[]
Returns Writer<S, A>

equals

equals(other: Writer<S, A>): boolean

- Defined in Writer.ts:54
Checks equality between two Writers of the same type.

Parameters
- other: Writer<S, A>
Returns boolean

eval

eval(): A

- Defined in Writer.ts:44
Returns the value at the end of a sequence of Writer computations.

Returns A

exec

exec(): S[]

- Defined in Writer.ts:49
Returns the story at the end of a sequence of Writer computations.

Returns S[]

fmap

fmap<B>(func: function): Writer<S, B>

- Defined in Writer.ts:75
Binds a new operation to this Writer.

Type parameters
- B
Parameters
- func: function
  - - (a: A): Writer<S, B>
    - Parameters
      - a: A
      Returns Writer<S, B>
Returns Writer<S, B>

isEmpty

isEmpty(): boolean

- Defined in Writer.ts:39
Returns boolean

listen

listen<B>(func: function): Writer<S, B>

- Defined in Writer.ts:84
Modifies the Writer to include changes to the value.

Type parameters
- B
Parameters
- func: function
  - - (w: Writer<S, A>): B
    - Parameters
      - w: Writer<S, A>
      Returns B
Returns Writer<S, B>

map

map<B>(func: function): Writer<S, B>

- Defined in Writer.ts:64
Applies a function to the accumulated value of a Writer.

Type parameters
- B
Parameters
- func: function
  - - (a: A): B
    - Parameters
      - a: A
      Returns B
Returns Writer<S, B>

on

on(callback: function): Writer<S, A>

- Defined in Writer.ts:89
Run a side effect on the value.

Parameters
- callback: function
  - - (a: A): void
    - Parameters
      - a: A
      Returns void
Returns Writer<S, A>

Static tell

tell<S, A>(story: S[]): Writer<S, A & object>

- Defined in Writer.ts:32
Creates a new Writer with an initial story and an empty value.

Type parameters
- S
- A
Parameters
- story: S[]
Returns Writer<S, A & object>

Static unit

unit<S, A>(a: A): Writer<S, A>

- Defined in Writer.ts:37
Creates a new Writer with an empty story and an initial value.

Type parameters
- S
- A
Parameters
- a: A
Returns Writer<S, A>

Static writer

writer<S, A>(story: S[], value: A): Writer<S, A>

- Defined in Writer.ts:27
Creates a new Writer with a story and a value.

Type parameters
- S
- A
Parameters
- story: S[]
- value: A
Returns Writer<S, A>

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