Function mapOrElse

mapOrElse<T, U, E>(
    orElseFn: (err: E) => U,
    mapFn: (t: T) => U,
    result: Result<T, E>,
): U
Map over a Result instance as in map and get out the value if result is Ok, or apply a function (orElseFn) to the value wrapped in the Err to get a default value.

Like mapOr but using a function to transform the error into a usable value instead of simply using a default value.

Examples
```
import { ok, err, mapOrElse } from 'true-myth/result';

const summarize = (s: string) => `The response was: '${s}'`;
const getReason = (err: { code: number, reason: string }) => err.reason;

const okResponse = ok("Things are grand here.");
const mappedOkAndUnwrapped = mapOrElse(getReason, summarize, okResponse);
console.log(mappedOkAndUnwrapped);  // The response was: 'Things are grand here.'

const errResponse = err({ code: 500, reason: 'Nothing at this endpoint!' });
const mappedErrAndUnwrapped = mapOrElse(getReason, summarize, errResponse);
console.log(mappedErrAndUnwrapped);  // Nothing at this endpoint!
```
Type Parameters
- T
  The type of the wrapped Ok value.
- U
  The type of the resulting value from applying mapFn to the Ok value or orElseFn to the Err value.
- E
  The type of the wrapped Err value.
Parameters
- orElseFn: (err: E) => U
  The function to apply to the wrapped Err value to get a usable value if result is an Err.
- mapFn: (t: T) => U
  The function to apply to the wrapped Ok value if result is an Ok.
- result: Result<T, E>
  The Result instance to map over.
Returns U
- Defined in result.ts:654
mapOrElse<T, U, E>(
orElseFn: (err: E) => U,
mapFn: (t: T) => U,
): (result: Result<T, E>) => U
Map over a Result instance as in map and get out the value if result is Ok, or apply a function (orElseFn) to the value wrapped in the Err to get a default value.

Like mapOr but using a function to transform the error into a usable value instead of simply using a default value.

Examples
```
import { ok, err, mapOrElse } from 'true-myth/result';

const summarize = (s: string) => `The response was: '${s}'`;
const getReason = (err: { code: number, reason: string }) => err.reason;

const okResponse = ok("Things are grand here.");
const mappedOkAndUnwrapped = mapOrElse(getReason, summarize, okResponse);
console.log(mappedOkAndUnwrapped);  // The response was: 'Things are grand here.'

const errResponse = err({ code: 500, reason: 'Nothing at this endpoint!' });
const mappedErrAndUnwrapped = mapOrElse(getReason, summarize, errResponse);
console.log(mappedErrAndUnwrapped);  // Nothing at this endpoint!
```
Type Parameters
- T
  The type of the wrapped Ok value.
- U
  The type of the resulting value from applying mapFn to the Ok value or orElseFn to the Err value.
- E
  The type of the wrapped Err value.
Parameters
- orElseFn: (err: E) => U
  The function to apply to the wrapped Err value to get a usable value if result is an Err.
- mapFn: (t: T) => U
  The function to apply to the wrapped Ok value if result is an Ok.
Returns (result: Result<T, E>) => U
- Defined in result.ts:659
mapOrElse<T, U, E>(
orElseFn: (err: E) => U,
): (mapFn: (t: T) => U) => (result: Result<T, E>) => U

Map over a Result instance as in map and get out the value if result is Ok, or apply a function (orElseFn) to the value wrapped in the Err to get a default value.

Like mapOr but using a function to transform the error into a usable value instead of simply using a default value.

Examples

import { ok, err, mapOrElse } from 'true-myth/result';

const summarize = (s: string) => `The response was: '${s}'`;
const getReason = (err: { code: number, reason: string }) => err.reason;

const okResponse = ok("Things are grand here.");
const mappedOkAndUnwrapped = mapOrElse(getReason, summarize, okResponse);
console.log(mappedOkAndUnwrapped);  // The response was: 'Things are grand here.'

const errResponse = err({ code: 500, reason: 'Nothing at this endpoint!' });
const mappedErrAndUnwrapped = mapOrElse(getReason, summarize, errResponse);
console.log(mappedErrAndUnwrapped);  // Nothing at this endpoint!

Type Parameters

T
The type of the wrapped Ok value.
U
The type of the resulting value from applying mapFn to the Ok value or orElseFn to the Err value.
E
The type of the wrapped Err value.

Parameters

orElseFn: (err: E) => U
The function to apply to the wrapped Err value to get a usable value if result is an Err.

Function mapOrElse

Examples

Type Parameters

Parameters

Returns U

Examples

Type Parameters

Parameters

Returns (result: Result<T, E>) => U

Examples

Type Parameters

Parameters

Returns (mapFn: (t: T) => U) => (result: Result<T, E>) => U

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