Function getInputSelectionText

packages/core/src/runtime/inputEditor.ts:253–266

(
  value: string,
  selectionStart: number | null | undefined,
  selectionEnd: number | null | undefined,
)

}

export function getInputSelectionText(
  value: string,
  selectionStart: number | null | undefined,
  selectionEnd: number | null | undefined,
): string | null {
  const selection = normalizeInputSelection(value, selectionStart, selectionEnd);
  if (!selection) return null;
  const [start, end] =
    selection.start <= selection.end
      ? [selection.start, selection.end]
      : [selection.end, selection.start];
  if (start >= end) return null;
  return value.slice(start, end);
}

function asUnicodeScalarString(codepoint: number): string {
  if (!Number.isFinite(codepoint)) return "\ufffd";