how to pass variable from callback function to function call?

Question

Here i am sending sensor data to database using simple javascript (johnny five) using this code

var five = require("johnny-five");
var pg = require("pg");
var conString = "pg://admin:raja@localhost:5432/data";
var client = new pg.Client(conString);

function call(n)
{
  client.connect();
  client.query("INSERT INTO sensordata (event) VALUES (n);");
}


var board = new five.Board();
board.on("ready", function() {

  var sensor = new five.Sensor.Digital(2);

  sensor.on("change", function() {
    var n = this.value;
    call(n);
  });
});

My question is can i pass the streaming data variable n in the sensor call back function to call method.

Answer 1

I think, what you're looking here is a simple query templating, supported by all sql clients:

client.query("INSERT INTO sensordata (event) VALUES ($1);", n);

This way you'll be able to pass the value of n variable to your SQL query.

Update: And you don't have to call client.connect() before every call to client.query . You should only call it once to establish DB connection, after that pg.Client will use it to send all subsequent requests.