Function assertUndefined

packages/vitest/src/utils.ts:242–249

(
  a: A | undefined,
  ..._: Array<never>
)

 * @since 4.0.0
 */
export function assertUndefined<A>(
  a: A | undefined,
  ..._: Array<never>
): asserts a is undefined {
  if (a !== undefined) {
    fail("Expected value to be undefined")
  }
}

/**
 * Asserts that `option` is `Some` and contains a value equal to `expected`.