insert method

StringBuilder insert(
  1. int index,
  2. String str
)

Inserts a string at the specified index.

index the index at which to insert str the string to insert Returns this StringBuilder for method chaining

Implementation

StringBuilder insert(int index, String str) {
  String current = _buffer.toString();
  if (index < 0 || index > current.length) {
    throw RangeError('Index out of range: $index');
  }

  String before = current.substring(0, index);
  String after = current.substring(index);

  _buffer.clear();
  _buffer.write(before);
  _buffer.write(str);
  _buffer.write(after);

  return this;
}