askRetro

Experimental, customizable event driven retrosheet event file processor for developing applications that analyze historical major league baseball data.

Askretro traverses each event file line by line and maintains the state of the game as each event (play, substitution, etc) occurs. It also emits events to which users can subscribe using callbacks that process the current game state and event information.

Installation

npm install askRetro

Game state

AskRetro maintains the game state at all times. The state object contains the following fields:

Field	Description
id	The retrosheet id of the game (eg, ANA201704070)
previousPlay	The play information from the previous line of the file
presentPlay	The play information from the line currently being processed
baseRunners	The baserunner object (see below)
lineups	The lineup objects (see below - 0 = visiting team, 1 = home team)
inning	The current inning
outs	The current number of outs
currentBatter	The retrosheet id of the current batter (eg., maybc001)
score	The score object (0 = visiting team, 1 = home team)
battingTeam	The team currently batting (0 = visiting team, 1 = home team)

baseRunners

Field	Description	Default
0	retrosheet id of the batter	N/A
1	retrosheet id of the runner on first	null
2	retrosheet id of the runner on	null
3	retrosheet id of the runner on third	null

batting lineup

Field	Description	Default
0	retrosheet id of the pitcher when a designated hitter is used	null
1	retrosheet id of the first batter
2	retrosheet id of the second batter
3	retrosheet id of the third batter
4	retrosheet id of the fourth batter
5	retrosheet id of the fifth batter
6	retrosheet id of the sixth batter
7	retrpsheet id of the seventh batter
8	retrosheet id of the eight batter
9	retrosheet id of the ninth batter

fielding lineup

Field	Description	Default
1	retrosheet id of the pitcher
2	retrosheet id of the catcher
3	retrosheet id of the first baseman
4	retrosheet id of the second baseman
5	retrosheet id of the third baseman
6	retrosheet id of the shortstop
7	retrosheet id of the left fielder
8	retrosheet id of the center fielder
9	retrosheet id of the right fielder
10	retrosheet id of the designated hitter (if applicable)
11	retrosheet id of a pinch hitter (when applicable)
12	retrosheet id of a pinch runner (when applicable)

Example state object

{
  id:'ANA201504120',
  previousPlay:{
    inning:2,
    team:0,
    id:'riosa002',
    count:'01',
    pitches:'CX',
    playInfo:'S9/L.1-2'
  },
  presentPlay:{
    inning:2,
    team:0,
    id:'peres002',
    count:'00',
    pitches:'X',
    playInfo:'S8/G.2-H;1-2'
  },
  baseRunners:{
    0:'peres002',
    1:'riosa002',
    2:'morak001',
    3:null
  },
  lineups:{
    0:{
      batting:{
        0:'venty001',
        1:'escoa003',
        2:'mousm001',
        3:'cainl001',
        4:'hosme001',
        5:'morak001',
        6:'riosa002',
        7:'peres002',
        8:'orlap001',
        9:'infao001'
      },
      fielding:{
        1:'venty001',
        2:'peres002',
        3:'hosme001',
        4:'infao001',
        5:'mousm001',
        6:'escoa003',
        7:'orlap001',
        8:'cainl001',
        9:'riosa002',
        10:'morak001'
      }
    },
    1:{
      batting:{
        0:'wilsc004',
        1:'aybae001',
        2:'troum001',
        3:'pujoa001',
        4:'joycm001',
        5:'freed001',
        6:'cronc002',
        7:'iannc001',
        8:'cowgc001',
        9:'featt001'
      },
      fielding:{
        1:'wilsc004',
        2:'iannc001',
        3:'pujoa001',
        4:'featt001',
        5:'freed001',
        6:'aybae001',
        7:'joycm001',
        8:'troum001',
        9:'cowgc001',
        10:'cronc002'
      }
    }
  },
  inning:2,
  outs:0,
  currentBatter:'peres002',
  score:{
    0:0,
    1:1
  },
  battingTeam:0

Available events

• newGame: triggered when a new game id is detected in the file, just before the game state is reset
• newInning: triggered at the end of an inning just before the inning is reset in the game state
• lineupChange: triggered once for each starter at the beginning of the game and again each time there is a substitution during the game.
• processInfo: triggered when the processor encounters an 'info' line in the file
• processStart: triggered when the processor encounters a 'start' line in the file
• processPlay: triggered when the processor encounters a 'play' line in the file
• processSub: triggered when the processor encounters a 'sub' line in the file
• end: triggered at the end of the game
• out: triggered whenever an out occurs
• run: triggered whenever a run is scored
• rbi: triggered whenever an rbi is credited to the hitter
• advanceRunners: triggered just before runners advance on any given play
• balk: triggered when the pitcher is charged with a balk
• caughtStealing: triggered when a runner is caught stealing
• defensiveIndifference: triggered when a runner is awarded a base due to defensive indifference
• hit: triggered when the batter gets a hit (single, double, triple, home run)
• hitByPitch: triggered when the batter is hit by a pitch
• error: triggered when a fielding error occurs
• flyBallOut: triggered when the batter hits into a fly ball out
• groundBallOut: triggered when the batter hits into a ground ball out
• otherAction: triggered when something strange happens
• pickoff: triggered when a runner is picked off a base
• stolenBase: triggered when a runner steals a base
• strikeout: triggered when a batter strikes out
• walk: triggered when a batter walks
• wildPitch: triggered when a pitcher is charged with a wild pitch
• beforeFileLoad: triggered just before a new file is loaded
• afterFileLoad: triggered after a file loads

Examples

Walk through all games from 2017 and console log all homeruns

'use strict';
const askRetro = require('askretro');

const startYear = 2017;
const endYear = 2017;

askRetro.configuration.configure({ startYear, endYear, loggingLevel: 'error' });

const logHomer = (hitter) => {
  console.log(`${hitter} just hit a home run!`);
}

const hit = (state, info) => {
  const play = info.playInfo;
  if (/^(H|HR)[1-9]*?$/.test(play)) logHomer(state.currentBatter);
};

askRetro.subscribe('hit', hit);

askRetro.processFiles()
  .then(() => {
    console.log('done');
  })
  .catch(err => {
    console.log(err);
  })