Interface Just<T>

A Just instance is the present variant instance of the Maybe type, representing the presence of a value which may be absent. For a full discussion, see the module docs.

Typeparam

T The type wrapped in this Just variant of Maybe.

Type Parameters

  • T

Hierarchy

  • MaybeImpl<T>
    • Just

Properties

isJust: true
isNothing: false
value: T

The wrapped value.

variant: "Just"

Just is always Variant.Just.

Methods

  • Method variant for and

    Type Parameters

    • U

    Parameters

    Returns Maybe<U>

  • Method variant for andThen

    Type Parameters

    • U

    Parameters

    • andThenFn: ((t) => Maybe<U>)

    Returns Maybe<U>

  • Method variant for ap

    Type Parameters

    • A

    • B

    Parameters

    Returns Maybe<B>

  • Method variant for equals

    Parameters

    Returns boolean

  • Method variant for get

    If you have a Maybe of an object type, you can do thatMaybe.get('a key') to look up the next layer down in the object.

    type DeepOptionalType = {
    something?: {
    with?: {
    deeperKeys?: string;
    }
    }
    };

    const fullySet: DeepType = {
    something: {
    with: {
    deeperKeys: 'like this'
    }
    }
    };

    const deepJust = Maybe.of(fullySet)
    .get('something')
    .get('with')
    .get('deeperKeys');

    console.log(deepJust); // Just('like this');

    const partiallyUnset: DeepType = { something: { } };

    const deepEmpty = Maybe.of(partiallyUnset)
    .get('something')
    .get('with')
    .get('deeperKeys');

    console.log(deepEmpty); // Nothing

    Type Parameters

    • K extends string | number | symbol

    Parameters

    • key: K

    Returns Maybe<NonNullable<T[K]>>

  • Method variant for map

    Type Parameters

    • U

    Parameters

    • mapFn: ((t) => U)
        • (t): U
        • Parameters

          • t: T

          Returns U

    Returns Maybe<U>

  • Method variant for mapOr

    Type Parameters

    • U

    Parameters

    • orU: U
    • mapFn: ((t) => U)
        • (t): U
        • Parameters

          • t: T

          Returns U

    Returns U

  • Method variant for mapOrElse

    Type Parameters

    • U

    Parameters

    • orElseFn: (() => U)
        • (): U
        • Returns U

    • mapFn: ((t) => U)
        • (t): U
        • Parameters

          • t: T

          Returns U

    Returns U

  • Method variant for match

    Type Parameters

    • U

    Parameters

    Returns U

  • Method variant for toString

    Returns string

  • Method variant for unwrapOr

    Type Parameters

    • U

    Parameters

    • defaultValue: U

    Returns T | U

  • Method variant for unwrapOrElse

    Type Parameters

    • U

    Parameters

    • elseFn: (() => U)
        • (): U
        • Returns U

    Returns T | U

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