code: function strcpy(dest, src, offset) {
    var origDestLen = dest.length;
    var start = dest.slice(0, offset);
    var end = dest.slice(offset + src.length);
    return (start + src + end).substr(0, origDestLen);
  }
docs: Produce a new string that would be the result of copying the contents of the string `src` onto `dest` at offset `offest`.