CODEWITHSUNDEEP
javascriptnode.jsasync.js
Jonathan
Jonathan

Reputation: 3024

Wait until forEach loop is finished?

Adding a callback straight after the forEach loop doesn't work. I'm new to node.js so any help would be appreciated, thanks.

This is for a Minecraft bot that logs players login and logout times. After I get kicked from the server I want to end all players sessions before attempting to rejoin but in the following code even though im using async.series it still doesn't wait until the first function is finished - is this due to the position of my callback?

bot.on('kicked', function(reason) {
  console.log("I got kicked for", reason, "lol");
  var timestamp = getTimestamp();

    async.series([
      function(callback) {
        console.log("logging out all players");
        logoutAllPlayers(timestamp, function(finished) {
          console.log("logged out all players " + finished);
          if (finished) {
            callback();
          }
        });
      },
      function(callback) { //don't execute until previous function has run completely
        //rejoin here
        bot = mineflayer.createBot(options);
        bindlisteners(bot);
      }
    ]);
});

...

Where is the correct place to put the callback?

function logoutAllPlayers(timestamp, callback) {
      findOnlinePlayers(function(onlinePlayers) {
          if (onlinePlayers.length > 0) {
              onlinePlayers.forEach(function(player) {
                var playerId = player.id;
                var username = player.username;

                async.waterfall([
                  function(callback) { //add logout event
                    addEvent(playerId, 2, timestamp, function(logoutEventId) {
                      console.log("[" + timestamp + "] " + "Created logout: " + logoutEventId + " for " + username + " (" + playerId +")");
                      callback(null, logoutEventId);
                    });
                  },
                  function(logoutEventId, callback) { //find players current session
                    findSession(playerId, function(sessionId, loginEventId) {
                      console.log("[" + timestamp + "] " + "Found session: " + sessionId +" for " + username + " (" + playerId +")");
                      callback(null, sessionId, loginEventId, logoutEventId); 
                    });
                  },
                  function(sessionId, loginEventId, logoutEventId, callback) { //get timestamps for login and logout events to find the duration of session
                    findEventTimestamp(loginEventId, function(loginTimestamp) {
                      findEventTimestamp(logoutEventId, function(logoutTimestamp) {
                        var difference = diffBetweenTimestamps(loginTimestamp, logoutTimestamp);
                        console.log("[" + timestamp + "] " + "Duration: " + difference + " for " + username);
                        callback(null, sessionId, logoutEventId, difference, callback);
                      }); 
                    });
                  },
                  function(sessionId, logoutEventId, difference, callback) { //end session and update online status
                    endSession(sessionId, logoutEventId, difference, function(callback) {
                      console.log("[" + timestamp + "] " + "Updated session: " + sessionId + " for " + username + " (" + playerId +")");
                      updatenOnlineStatus(playerId, false); 
                    });     
                  }
                ]);
            });
            callback(true);
          }
      });
    }

Upvotes: 2

Views: 3126

Answers (1)

loganfsmyth
loganfsmyth

Reputation: 161657

In logoutAllPlayers, you are calling callback(true); before your async.waterfall call has finished its steps.

Instead you should call that final waterfall callback from //end session and update online statusand then change the last line of your waterfall to have a completion callback.

async.waterfall([
  // ...
], function(){
  callback(true);
});

Upvotes: 5

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