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Function: tapNone()

Call Signature​

tapNone<T>(option, fn): Option<T>

Defined in: option/tap/index.ts:77

Performs a side effect when the Option is None.

If the Option is None, calls the function. Returns the original Option unchanged.

Useful for logging missing values or debugging.

Type Parameters​

T​

T

Parameters​

option​

Option<T>

The Option to tap

fn​

() => void

Side effect function

Returns​

Option<T>

The original Option

Example​

// Data-first
tapNone(none(), () => console.log('No value'))
// Logs: "No value"
// => None

// Data-last (in pipe)
pipe(
  findUser(id),
  tapNone(() => console.log('User not found')),
  unwrapOr(guestUser)
)

See​

tap - for side effects on Some

Call Signature​

tapNone<T>(fn): (option) => Option<T>

Defined in: option/tap/index.ts:78

Performs a side effect when the Option is None.

If the Option is None, calls the function. Returns the original Option unchanged.

Useful for logging missing values or debugging.

Type Parameters​

T​

T

Parameters​

fn​

() => void

Side effect function

Returns​

The original Option

(option): Option<T>

Parameters​

option​

Option<T>

Returns​

Option<T>

Example​

// Data-first
tapNone(none(), () => console.log('No value'))
// Logs: "No value"
// => None

// Data-last (in pipe)
pipe(
  findUser(id),
  tapNone(() => console.log('User not found')),
  unwrapOr(guestUser)
)

See​

tap - for side effects on Some