const YahooFantasy = require('yahoo-fantasy');
const yf = new YahooFantasy(
  Y!APPLICATION_KEY,
  Y!APPLICATION_SECRET,
  tokenCallbackFn, // optional
  redirectUri // optional
);

yf.setUserToken(
  Y!OAuthAccessToken
);

// promise based
try {
  const settings = await yf.league.settings(league_key);
} catch (e) {
  // handle error
}

// callback based
yf.league.settings(league_key, callbackFn);

{
  "draft_type": "live",
  "is_auction_draft": "1",
  "scoring_type": "head",
  "persistent_url": "http://baseball.fantasysports.yahoo.com/league/freddybaseball",
  "uses_playoff": "1",
  "has_playoff_consolation_games": true,
  "playoff_start_week": "23",
  "uses_playoff_reseeding": 0,
  "uses_lock_eliminated_teams": 0,
  "num_playoff_teams": "8",
  "num_playoff_consolation_teams": 0,
  "uses_roster_import": "1",
  "roster_import_deadline": "2014-03-06",
  "waiver_type": "R",
  "waiver_rule": "all",
  "uses_faab": "0",
  "draft_time": "1395361800",
  "post_draft_players": "W",
  "max_teams": "12",
  "waiver_time": "2",
  "trade_end_date": "2014-08-17",
  "trade_ratify_type": "commish",
  "trade_reject_time": "2",
  "player_pool": "ALL",
  "cant_cut_list": "yahoo",
  "is_publicly_viewable": "1",
  "roster_positions": [
    {
      "position": "C",
      "position_type": "B",
      "count": 1
    },
    {
      "position": "1B",
      "position_type": "B",
      "count": 1
    },
    {
      "position": "2B",
      "position_type": "B",
      "count": 1
    },
    {
      "position": "3B",
      "position_type": "B",
      "count": 1
    },
    {
      "position": "SS",
      "position_type": "B",
      "count": 1
    },
    {
      "position": "OF",
      "position_type": "B",
      "count": 3
    },
    {
      "position": "Util",
      "position_type": "B",
      "count": 1
    },
    {
      "position": "SP",
      "position_type": "P",
      "count": 4
    },
    {
      "position": "RP",
      "position_type": "P",
      "count": 2
    },
    {
      "position": "BN",
      "count": 5
    },
    {
      "position": "DL",
      "count": "2"
    }
  ],
  "stat_categories": [
    {
      "stat_id": 60,
      "enabled": "1",
      "name": "H/AB",
      "display_name": "H/AB",
      "sort_order": "1",
      "position_type": "B",
      "stat_position_types": [
        {
          "position_type": "B",
          "is_only_display_stat": "1"
        }
      ],
      "is_only_display_stat": "1"
    },
    {
      "stat_id": 7,
      "enabled": "1",
      "name": "Runs",
      "display_name": "R",
      "sort_order": "1",
      "position_type": "B",
      "stat_position_types": [
        {
          "position_type": "B"
        }
      ]
    },
    {
      "stat_id": 12,
      "enabled": "1",
      "name": "Home Runs",
      "display_name": "HR",
      "sort_order": "1",
      "position_type": "B",
      "stat_position_types": [
        {
          "position_type": "B"
        }
      ]
    },
    {
      "stat_id": 13,
      "enabled": "1",
      "name": "Runs Batted In",
      "display_name": "RBI",
      "sort_order": "1",
      "position_type": "B",
      "stat_position_types": [
        {
          "position_type": "B"
        }
      ]
    },
    {
      "stat_id": 16,
      "enabled": "1",
      "name": "Stolen Bases",
      "display_name": "SB",
      "sort_order": "1",
      "position_type": "B",
      "stat_position_types": [
        {
          "position_type": "B"
        }
      ]
    },
    {
      "stat_id": 3,
      "enabled": "1",
      "name": "Batting Average",
      "display_name": "AVG",
      "sort_order": "1",
      "position_type": "B",
      "stat_position_types": [
        {
          "position_type": "B"
        }
      ]
    },
    {
      "stat_id": 50,
      "enabled": "1",
      "name": "Innings Pitched",
      "display_name": "IP",
      "sort_order": "1",
      "position_type": "P",
      "stat_position_types": [
        {
          "position_type": "P",
          "is_only_display_stat": "1"
        }
      ],
      "is_only_display_stat": "1"
    },
    {
      "stat_id": 28,
      "enabled": "1",
      "name": "Wins",
      "display_name": "W",
      "sort_order": "1",
      "position_type": "P",
      "stat_position_types": [
        {
          "position_type": "P"
        }
      ]
    },
    {
      "stat_id": 32,
      "enabled": "1",
      "name": "Saves",
      "display_name": "SV",
      "sort_order": "1",
      "position_type": "P",
      "stat_position_types": [
        {
          "position_type": "P"
        }
      ]
    },
    {
      "stat_id": 42,
      "enabled": "1",
      "name": "Strikeouts",
      "display_name": "K",
      "sort_order": "1",
      "position_type": "P",
      "stat_position_types": [
        {
          "position_type": "P"
        }
      ]
    },
    {
      "stat_id": 26,
      "enabled": "1",
      "name": "Earned Run Average",
      "display_name": "ERA",
      "sort_order": "0",
      "position_type": "P",
      "stat_position_types": [
        {
          "position_type": "P"
        }
      ]
    },
    {
      "stat_id": 27,
      "enabled": "1",
      "name": "(Walks + Hits)/ Innings Pitched",
      "display_name": "WHIP",
      "sort_order": "0",
      "position_type": "P",
      "stat_position_types": [
        {
          "position_type": "P"
        }
      ]
    }
  ],
  "max_adds": "31",
  "season_type": "full",
  "min_innings_pitched": "30",
  "league": {
    "league_key": "328.l.34014",
    "league_id": "34014",
    "name": "Freddy Beach Baseball",
    "url": "http://baseball.fantasysports.yahoo.com/b1/34014",
    "draft_status": "postdraft",
    "num_teams": 12,
    "edit_key": "2014-11-13",
    "weekly_deadline": "intraday",
    "league_update_timestamp": "1411979069",
    "scoring_type": "head",
    "league_type": "private",
    "renew": "308_51222",
    "renewed": "",
    "short_invitation_url": "https://yho.com/mlb?l=34014&k=0a2bf56970bb200c",
    "is_pro_league": "0",
    "current_week": "25",
    "start_week": "1",
    "start_date": "2014-03-22",
    "end_week": "25",
    "end_date": "2014-09-28",
    "is_finished": 1
  }
}