Function initialIndex

src/setup/prompt.ts:30–36

(
  options: Array<{ value: T }>,
  defaultValue: T,
)

/** Resolve the starting index for a select list from its default value. Pure → testable. */
export function initialIndex<T extends string>(
  options: Array<{ value: T }>,
  defaultValue: T,
): number {
  const i = options.findIndex(o => o.value === defaultValue);
  return i >= 0 ? i : 0;
}

/** Visible width of a string: length with ANSI SGR (colour/dim) escapes removed. Pure → testable. */
export function displayWidth(s: string): number {