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Function: unwrapOrElse()

Call Signature​

unwrapOrElse<T, E>(result, fn): T

Defined in: result/unwrap/index.ts:94

Extracts the value from an Ok Result or computes a fallback from the error.

Unlike unwrapOr, this allows you to compute the default value lazily and access the error for decision-making.

Type Parameters​

T​

T

E​

E

Parameters​

result​

Result<T, E>

The Result to unwrap

fn​

(error) => T

Function to compute fallback from error

Returns​

T

The value from Ok or the computed fallback

Example​

// Data-first
unwrapOrElse(ok(42), () => 0) // => 42
unwrapOrElse(err('fail'), e => {
  console.error(e)
  return 0
}) // logs 'fail', returns 0

// Data-last (in pipe)
pipe(
  fetchUser(id),
  unwrapOrElse(error => {
    logError(error)
    return guestUser
  })
)

See​

unwrapOr - for static default values

Call Signature​

unwrapOrElse<T, E>(fn): (result) => T

Defined in: result/unwrap/index.ts:95

Extracts the value from an Ok Result or computes a fallback from the error.

Unlike unwrapOr, this allows you to compute the default value lazily and access the error for decision-making.

Type Parameters​

T​

T

E​

E

Parameters​

fn​

(error) => T

Function to compute fallback from error

Returns​

The value from Ok or the computed fallback

(result): T

Parameters​

result​

Result<T, E>

Returns​

T

Example​

// Data-first
unwrapOrElse(ok(42), () => 0) // => 42
unwrapOrElse(err('fail'), e => {
  console.error(e)
  return 0
}) // logs 'fail', returns 0

// Data-last (in pipe)
pipe(
  fetchUser(id),
  unwrapOrElse(error => {
    logError(error)
    return guestUser
  })
)

See​

unwrapOr - for static default values