# operator [] method

String operator [] (int index)
override

Returns the object at the given `index` in the list or throws a RangeError if `index` is out of bounds.

## Implementation

    String operator [](int index) {
      if (JS("bool", "# >>> 0 !== # || # >= #", index, index, index, length))
        throw new RangeError.index(index, this);
      return JS("String", "#[#]", this, index);
    }