Updated Example (markdown)

Example.md

@@ -4,55 +4,41 @@ You'll need to first "create table visit (date date)" in your postgres database
 
 ```javascript
 var http = require('http');
-var pg = require('pg');
+var Pool = require('pg').Pool;
 
-var conString = "postgres://postgres@localhost:5432/postgres";
+// by default the pool will use the same environment variables
+// as psql, pg_dump, pg_restore etc:
+// https://www.postgresql.org/docs/9.5/static/libpq-envars.html
+
+// you can optionally supply other values
+var config = {
+  host: 'localhost',
+  user: 'foo',
+  password: 'bar',
+  database: 'my_db',
+};
+
+var pool = new Pool(config)
 
 var server = http.createServer(function(req, res) {
 
-  // get a pg client from the connection pool
-  pg.connect(conString, function(err, client, done) {
+  var onError = function() {
+    res.writeHead(500, {'content-type': 'text/plain'});
+    res.end('An error occurred');
+  };
 
-    var handleError = function(err) {
-      // no error occurred, continue with the request
-      if(!err) return false;
+  pool.query('INSERT INTO visit (date) VALUES ($1)', [new Date()], function(err) {
+    if (err) return onError();
 
-      // An error occurred, remove the client from the connection pool.
-      // A truthy value passed to done will remove the connection from the pool
-      // instead of simply returning it to be reused.
-      // In this case, if we have successfully received a client (truthy)
-      // then it will be removed from the pool.
-      if(client){
-        done(client);
-      }
-      res.writeHead(500, {'content-type': 'text/plain'});
-      res.end('An error occurred');
-      return true;
-    };
-
-    // handle an error from the connection
-    if(handleError(err)) return;
-    
-    // record the visit
-    client.query('INSERT INTO visit (date) VALUES ($1)', [new Date()], function(err, result) {
-      
+    // get the total number of visits today (including the current visit)
+    pool.query('SELECT COUNT(date) AS count FROM visit', function(err, result) {
       // handle an error from the query
-      if(handleError(err)) return;
-
-      // get the total number of visits today (including the current visit)
-      client.query('SELECT COUNT(date) AS count FROM visit', function(err, result) {
-
-        // handle an error from the query
-        if(handleError(err)) return;
-
-        // return the client to the connection pool for other requests to reuse
-        done();
-        res.writeHead(200, {'content-type': 'text/plain'});
-        res.end('You are visitor number ' + result.rows[0].count);
-      });
+      if(err) return onError();
+      res.writeHead(200, {'content-type': 'text/plain'});
+      res.end('You are visitor number ' + result.rows[0].count);
     });
   });
-})
+});
 
 server.listen(3001)
 ```