insertTextInFragment static method

bool insertTextInFragment(Fragment fragment, int offset, String text)

Inserts text in fragment at offset. Returns false if offset is out of range. Optimised edge cases (prepend / append) avoid temp substring allocations.

Implementation

static bool insertTextInFragment(Fragment fragment, int offset, String text) {
  if (offset < 0 || offset > fragment.text.length) return false;
  if (text.isEmpty) return true;
  if (offset == 0) {
    fragment.text = text + fragment.text;
  } else if (offset == fragment.text.length) {
    fragment.text = fragment.text + text;
  } else {
    fragment.text = fragment.text.substring(0, offset) +
        text +
        fragment.text.substring(offset);
  }
  return true;
}