Function normalizeInputCursor

packages/core/src/runtime/inputEditor.ts:209–223

(value: string, cursor: number)

 * Clamps to [0, value.length] and snaps to the previous boundary.
 */
export function normalizeInputCursor(value: string, cursor: number): number {
  const c = clampInputCursor(value, cursor);
  if (c === 0 || c === value.length) return c;

  let off = 0;
  let last = 0;
  while (off < value.length) {
    const end = nextClusterEnd(value, off);
    if (end === c) return c;
    if (end > c) return last;
    last = end;
    off = end;
  }
  return value.length;
}

function normalizeInputCursorForward(value: string, cursor: number): number {
  const c = clampInputCursor(value, cursor);