Class Nothing

An absent Maybe.

Hierarchy

Maybe.Syntax
- Nothing

Index

Properties

Methods

[cmb] [cmp] [eq] [iterator] and andThen andThenGo filter getOr getOrElse isJust isNothing map mapNullish or orElse toNullish unwrap zipWith

Properties

`Readonly` kind

kind: NOTHING = Kind.NOTHING

The property that discriminates Maybe.

`Static` `Readonly` singleton

singleton: Nothing = ...

The singleton instance of Nothing.

Remarks

The nothing constant is a more accessible alias for this object.

Methods

[cmb]

[cmb]<T>(this, that): Maybe<T>
If this and that Maybe are Just, combine their values; otherwise, return the first Maybe that is not Nothing.
Type Parameters
- T extends Semigroup<T>
Parameters
- this: Maybe<T>
- that: Maybe<T>
Returns Maybe<T>
Inherited from Syntax.[cmb]
- Defined in maybe.ts:359

[cmp]

[cmp]<T>(this, that): Ordering
Compare this and that Maybe to determine their ordering.
Type Parameters
- T extends Ord<T>
Parameters
- this: Maybe<T>
- that: Maybe<T>
Returns Ordering

Remarks
When ordered, Nothing always compares as less than Just. If both are Just, their values are compared to determine the ordering.
Inherited from Syntax.[cmp]
- Defined in maybe.ts:346

[eq]

[eq]<T>(this, that): boolean
Compare this and that Maybe to determine their equality.
Type Parameters
- T extends Eq<T>
Parameters
- this: Maybe<T>
- that: Maybe<T>
Returns boolean

Remarks
Two Maybe are equal if they are both Nothing, or they are both both Just and their values are equal.
Inherited from Syntax.[eq]
- Defined in maybe.ts:331

[iterator]

[iterator](): Generator<Maybe<never>, never, unknown>
Returns Generator<Maybe<never>, never, unknown>
- Defined in maybe.ts:519

and

and<T1>(this, that): Maybe<T1>
If this Maybe is Just, ignore its value and return that Maybe.
Type Parameters
- T1
Parameters
- this: Maybe<any>
- that: Maybe<T1>
Returns Maybe<T1>
Inherited from Syntax.and
- Defined in maybe.ts:447

andThen

andThen<T, T1>(this, f): Maybe<T1>
If this Maybe is Just, apply a function to its value to return another Maybe.
Type Parameters
- T
- T1
Parameters
- this: Maybe<T>
- f: ((val) => Maybe<T1>)
  - - (val): Maybe<T1>
    - Parameters
      
      val: T
      
      Returns Maybe<T1>
Returns Maybe<T1>
Inherited from Syntax.andThen
- Defined in maybe.ts:432

andThenGo

andThenGo<T, T1>(this, f): Maybe<T1>
If this Maybe is Just, apply a generator function to its value to its value to return another Maybe.
Type Parameters
- T
- T1
Parameters
- this: Maybe<T>
- f: ((val) => Maybe.Go<T1>)
  - - (val): Maybe.Go<T1>
    - Parameters
      
      val: T
      
      Returns Maybe.Go<T1>
Returns Maybe<T1>
Inherited from Syntax.andThenGo
- Defined in maybe.ts:440

filter

filter<T, T1>(this, f): Maybe<T1>
If this Maybe is Just, apply a predicate to filter its value.
Type Parameters
- T
- T1
Parameters
- this: Maybe<T>
- f: ((val) => val is T1)
  - - (val): val is T1
    - Parameters
      
      val: T
      
      Returns val is T1
Returns Maybe<T1>

Remarks
If the predicate returns false, return Nothing.
Inherited from Syntax.filter
- Defined in maybe.ts:472
filter<T>(this, f): Maybe<T>
Type Parameters
- T
Parameters
- this: Maybe<T>
- f: ((val) => boolean)
  - - (val): boolean
    - Parameters
      
      val: T
      
      Returns boolean
Returns Maybe<T>
Inherited from Syntax.filter
- Defined in maybe.ts:477

getOr

getOr<T, T1>(this, fallback): T | T1
If this Maybe is Just, extract its value; otherwise, return a fallback value.
Type Parameters
- T
- T1
Parameters
- this: Maybe<T>
- fallback: T1
Returns T | T1
Inherited from Syntax.getOr
- Defined in maybe.ts:403

getOrElse

getOrElse<T, T1>(this, f): T | T1
If this Maybe is Just, extract its value; otherwise, invoke a function to return a fallback value.
Type Parameters
- T
- T1
Parameters
- this: Maybe<T>
- f: (() => T1)
  - - (): T1
    - Returns T1
Returns T | T1
Inherited from Syntax.getOrElse
- Defined in maybe.ts:395

isJust

isJust<T>(this): this is Just<T>
Test whether this Maybe is Just.
Type Parameters
- T
Parameters
- this: Maybe<T>
Returns this is Just<T>
Inherited from Syntax.isJust
- Defined in maybe.ts:375

isNothing

isNothing(this): this is Nothing
Test whether this Maybe is Nothing.
Parameters
- this: Maybe<any>
Returns this is Nothing
Inherited from Syntax.isNothing
- Defined in maybe.ts:370

map

map<T, T1>(this, f): Maybe<T1>
If this Maybe is Just, apply a function to map its value.
Type Parameters
- T
- T1
Parameters
- this: Maybe<T>
- f: ((val) => T1)
  - - (val): T1
    - Parameters
      
      val: T
      
      Returns T1
Returns Maybe<T1>
Inherited from Syntax.map
- Defined in maybe.ts:496

mapNullish

mapNullish<T, T1>(this, f): Maybe<T1>
If this Maybe is Just, apply a partial function to map its value.
Type Parameters
- T
- T1
Parameters
- this: Maybe<T>
- f: ((val) => undefined | null | T1)
  - - (val): undefined | null | T1
    - Parameters
      
      val: T
      
      Returns undefined | null | T1
Returns Maybe<T1>

Remarks
If the function returns null or undefined, return Nothing.
Inherited from Syntax.mapNullish
- Defined in maybe.ts:458

or

or<T, T1>(this, that): Maybe<T | T1>
If this Maybe is Nothing, return that Maybe.
Type Parameters
- T
- T1
Parameters
- this: Maybe<T>
- that: Maybe<T1>
Returns Maybe<T | T1>
Inherited from Syntax.or
- Defined in maybe.ts:424

orElse

orElse<T, T1>(this, f): Maybe<T | T1>
If this Maybe is Nothing, invoke a function to return a fallback Maybe.
Type Parameters
- T
- T1
Parameters
- this: Maybe<T>
- f: (() => Maybe<T1>)
  - - (): Maybe<T1>
    - Returns Maybe<T1>
Returns Maybe<T | T1>
Inherited from Syntax.orElse
- Defined in maybe.ts:419

toNullish

toNullish<T>(this): undefined | T
If this Maybe is Just, extract its value; otherwise, return undefined.
Type Parameters
- T
Parameters
- this: Maybe<T>
Returns undefined | T
Inherited from Syntax.toNullish
- Defined in maybe.ts:411

unwrap

unwrap<T, T1, T2>(this, ifNothing, unwrapJust): T1 | T2
If this Maybe is Just, apply a function to extract its value; otherwise, invoke a function to return a fallback value.
Type Parameters
- T
- T1
- T2
Parameters
- this: Maybe<T>
- ifNothing: (() => T1)
  - - (): T1
    - Returns T1
- unwrapJust: ((val) => T2)
  - - (val): T2
    - Parameters
      
      val: T
      
      Returns T2
Returns T1 | T2
Inherited from Syntax.unwrap
- Defined in maybe.ts:383

zipWith

zipWith<T, T1, T2>(this, that, f): Maybe<T2>
If this and that Maybe are Just, apply a function to combine their values.
Type Parameters
- T
- T1
- T2
Parameters
- this: Maybe<T>
- that: Maybe<T1>
- f: ((lhs, rhs) => T2)
  - - (lhs, rhs): T2
    - Parameters
      
      lhs: T
      
      rhs: T1
      
      Returns T2
Returns Maybe<T2>
Inherited from Syntax.zipWith
- Defined in maybe.ts:487

Class Nothing

Hierarchy

Index

Properties

Methods

Properties

Readonly kind

Static Readonly singleton

Remarks

Methods

[cmb]

Type Parameters

T extends Semigroup<T>

Parameters

this: Maybe<T>

that: Maybe<T>

Returns Maybe<T>

[cmp]

Type Parameters

T extends Ord<T>

Parameters

this: Maybe<T>

that: Maybe<T>

Returns Ordering

Remarks

[eq]

Type Parameters

T extends Eq<T>

Parameters

this: Maybe<T>

that: Maybe<T>

Returns boolean

Remarks

[iterator]

Returns Generator<Maybe<never>, never, unknown>

and

Type Parameters

T1

Parameters

this: Maybe<any>

that: Maybe<T1>

Returns Maybe<T1>

andThen

Type Parameters

T

T1

Parameters

this: Maybe<T>

f: ((val) => Maybe<T1>)

Parameters

val: T

Returns Maybe<T1>

Returns Maybe<T1>

andThenGo

Type Parameters

T

T1

Parameters

this: Maybe<T>

f: ((val) => Maybe.Go<T1>)

Parameters

val: T

Returns Maybe.Go<T1>

Returns Maybe<T1>

filter

Type Parameters

T

T1

Parameters

this: Maybe<T>

f: ((val) => val is T1)

Parameters

val: T

Returns val is T1

Returns Maybe<T1>

Remarks

Type Parameters

T

Parameters

this: Maybe<T>

`Readonly` kind

`Static` `Readonly` singleton