Added transaction helper

Author: cemremengu

index.js

@@ -3,6 +3,39 @@
 const fp = require('fastify-plugin')
 var pg = require('pg')
 
+function transactionHelper (query, values) {
+  return new Promise((resolve, reject) => {
+    this.connect((err, client, done) => {
+      if (err) reject(err)
+
+      const shouldAbort = (err) => {
+        if (err) {
+          client.query('ROLLBACK', (err) => {
+            done()
+            reject(err)
+          })
+        }
+        return !!err
+      }
+
+      client.query('BEGIN', (err) => {
+        if (shouldAbort(err)) reject(err)
+        client.query(query, values, (err, res) => {
+          if (shouldAbort(err)) reject(err)
+
+          client.query('COMMIT', (err) => {
+            done()
+            if (err) {
+              reject(err)
+            }
+            resolve(res)
+          })
+        })
+      })
+    })
+  })
+}
+
 function fastifyPostgres (fastify, options, next) {
   if (options.native) {
     delete options.native
@@ -21,7 +54,8 @@ function fastifyPostgres (fastify, options, next) {
     connect: pool.connect.bind(pool),
     pool: pool,
     Client: pg.Client,
-    query: pool.query.bind(pool)
+    query: pool.query.bind(pool),
+    transact: transactionHelper.bind(pool)
   }
 
   if (name) {

test.js

@@ -253,3 +253,42 @@ test('fastify.pg.test should throw with duplicate connection names', t => {
     t.is(err.message, 'Connection name has already been registered: test')
   })
 })
+
+test('fastify.pg.test use transact util', t => {
+  t.plan(2)
+
+  const fastify = Fastify()
+
+  fastify.register(fastifyPostgres, {
+    name: 'test',
+    connectionString: 'postgres://postgres@localhost/postgres'
+  })
+
+  fastify.ready(err => {
+    t.error(err)
+    fastify.pg.test
+      .query('CREATE TABLE users(username VARCHAR (50) NOT NULL)')
+      .then(result => {
+        fastify.pg.test
+          .transact('INSERT INTO users(username) VALUES($1)', ['brianc'])
+          .then(result => {
+            fastify.pg.test
+              .query('SELECT * FROM users')
+              .then(result => {
+                t.ok(result.rows[0].one === 'brianc')
+              }).catch(err => {
+                t.fail(err)
+                fastify.close()
+              })
+          })
+          .catch(err => {
+            t.fail(err)
+            fastify.close()
+          })
+      })
+      .catch(err => {
+        t.fail(err)
+        fastify.close()
+      })
+  })
+})