safeCallback

Runs a callback in a safe block. If the callback throws or returns a rejected promise, the function returns or resolves to a "safe-callback-error" typed Left instead of propagating the error. If the callback returns an Either, it is kept as-is. Promise results are handled after resolution.

Interactive example

Syntax

function safeCallback<
	const GenericOutput extends unknown
>(
	theFunction: () => GenericOutput
): Extract<ComputeSafeCallbackResult<GenericOutput>, any>;

Parameters

• theFunction: Callback to execute in a safe block. It can return a direct value, an Either, or a promise of either.

Return value

• If the callback returns a Left or Right: the Either is returned as-is.
• If the callback succeeds with a non-Either value: the value is wrapped in SafeCallbackSuccess.
• If the callback returns a promise: the resolved value follows the same rules.
• If the callback throws or the promise rejects: SafeCallbackError (left("safe-callback-error", error)) is returned or resolved.

See also

• left – Build a typed Left.
• whenHasInformation – Pattern match on "safe-callback-error".