kata_js_sfm_tcp.js

// https://www.codewars.com/kata/54acc128329e634e9a000362/train/javascript


 function traverseTCPStates(eventList){
    var state = "CLOSED";  
    
    var states = { 
      CLOSED : { APP_PASSIVE_OPEN : "LISTEN", APP_ACTIVE_OPEN : "SYN_SENT" },
      LISTEN: { RCV_SYN : "SYN_RCVD", APP_SEND : "SYN_SENT", APP_CLOSE : "CLOSED" },
      SYN_RCVD: { APP_CLOSE : "FIN_WAIT_1", RCV_ACK : "ESTABLISHED" },
      SYN_SENT: { RCV_SYN : "SYN_RCVD", RCV_SYN_ACK : "ESTABLISHED", APP_CLOSE : "CLOSED" },
      ESTABLISHED: { APP_CLOSE : "FIN_WAIT_1", RCV_FIN : "CLOSE_WAIT" },
      FIN_WAIT_1: { RCV_FIN : "CLOSING", RCV_FIN_ACK : "TIME_WAIT", RCV_ACK : "FIN_WAIT_2" },
      CLOSING: { RCV_ACK : "TIME_WAIT" },
      FIN_WAIT_2: { RCV_FIN : "TIME_WAIT" },
      TIME_WAIT: { APP_TIMEOUT : "CLOSED" },
      CLOSE_WAIT: { APP_CLOSE : "LAST_ACK" },
      LAST_ACK: { RCV_ACK : "CLOSED" },
      ERROR: {}
    };
  
    return eventList.reduce(function(state, input) { return states[state][input] || "ERROR"; }, state);
}
 

console.log(traverseTCPStates(["APP_ACTIVE_OPEN","RCV_SYN_ACK","RCV_FIN"]), "- CLOSE_WAIT")
console.log(traverseTCPStates(["APP_PASSIVE_OPEN",  "RCV_SYN","RCV_ACK"]), "- ESTABLISHED")    
console.log(traverseTCPStates(["APP_ACTIVE_OPEN","RCV_SYN_ACK","RCV_FIN","APP_CLOSE"]), "- LAST_ACK")
console.log(traverseTCPStates(["APP_ACTIVE_OPEN"]), "- SYN_SENT")
console.log(traverseTCPStates(["APP_PASSIVE_OPEN","RCV_SYN","RCV_ACK","APP_CLOSE","APP_SEND"]), "- ERROR")