Interface Err<T, E>

An Err instance is the failure variant instance of the Result type, representing a failure outcome from an operation which may fail. For a full discussion, see the module docs.

Typeparam

T The type which would be wrapped in an Ok variant of Result.

Typeparam

E The type wrapped in this Err variant of Result.

interface Err<T, E> {
    error: E;
    isErr: true;
    isOk: false;
    variant: "Err";
    and<U>(mAnd): Result<U, E>;
    andThen<U>(andThenFn): Result<U, E>;
    ap<A, B>(this, r): Result<B, E>;
    cast<U>(): Result<U, E>;
    equals(comparison): boolean;
    map<U>(mapFn): Result<U, E>;
    mapErr<F>(mapErrFn): Result<T, F>;
    mapOr<U>(orU, mapFn): U;
    mapOrElse<U>(orElseFn, mapFn): U;
    match<U>(matcher): U;
    or<F>(orResult): Result<T, F>;
    orElse<F>(orElseFn): Result<T, F>;
    toJSON(): ResultJSON<T, E>;
    toString(): string;
    unwrapOr<U>(defaultValue): T | U;
    unwrapOrElse<U>(elseFn): T | U;
}

Type Parameters

  • T
  • E

Hierarchy

  • Omit<ResultImpl<T, E>, "value" | "cast">
    • Err

Properties

error isErr isOk variant

Methods

and andThen ap cast equals map mapErr mapOr mapOrElse match or orElse toJSON toString unwrapOr unwrapOrElse

Properties

error

error: E

The wrapped error value.

isErr

isErr: true

isOk

isOk: false

Readonly variant

variant: "Err"

Err is always Variant.Err.

Methods

and

andThen

ap

cast

equals

  • equals(comparison): boolean

  • Method variant for equals

    Parameters

    Returns boolean

map

  • map<U>(mapFn): Result<U, E>

  • Method variant for map

    Type Parameters

    • U

    Parameters

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

        • Parameters

          Returns U

    Returns Result<U, E>

mapErr

  • mapErr<F>(mapErrFn): Result<T, F>

  • Method variant for mapErr

    Type Parameters

    • F

    Parameters

    • mapErrFn: ((e) => F)
        • (e): F

        • Parameters

          Returns F

    Returns Result<T, F>

mapOr

  • mapOr<U>(orU, mapFn): U

  • Method variant for mapOr

    Type Parameters

    • U

    Parameters

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

        • Parameters

          Returns U

    Returns U

mapOrElse

  • mapOrElse<U>(orElseFn, mapFn): U

  • Method variant for mapOrElse

    Type Parameters

    • U

    Parameters

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

        • Parameters

          • err: E

          Returns U

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

        • Parameters

          Returns U

    Returns U

match

or

orElse

toJSON

toString

  • toString(): string

  • Method variant for toString

    Returns string

unwrapOr

  • unwrapOr<U>(defaultValue): T | U

  • Method variant for unwrapOr

    Type Parameters

    • U = T

    Parameters

    • defaultValue: U

    Returns T | U

unwrapOrElse

  • unwrapOrElse<U>(elseFn): T | U

  • Method variant for unwrapOrElse

    Type Parameters

    • U

    Parameters

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

        • Parameters

          • error: E

          Returns U

    Returns T | U

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