Where to Put subscription.pull when want to get the publish data Google Cloud pub/sub NODE JS

So i've tried to develop some pub/sub system based on node js

i am using express post request to publish the data that i wanted. it's send the data well, but my question is where should i put my code for the subscription

Right now i put the code at the root of my file like this

pubSub.subscribe()
.then(({results, subscription}) => {
    results[0].data.forEach((item) => {
        let key = ['UserId', fakeId(1, 100), 'FeedId', fakeId(100, 200), 'plugin', fakeId(1, 100)]
        upsert(key, item, () => {
            console.log('Sync Success')
            console.log(item)
        }, error => console.error(error))
    })
    subscription.ack(results.map((result) => result.ackId));
})
.catch(error => console.error(error))

i have some helper to subscribe like this

function subscribe () {
const subscription = pubSub.subscription('plugin_subscription')

return new Promise ((resolve, reject) => {
    return subscription.pull((error, results) => {
        console.log('ini ke trigger')
        if (error) reject(error)
        resolve({results, subscription})
    })
})

}

well it's kind of only work once. if i publish message i dont' have any response log from the subscriber, but if i restart the node js server my log is show that i successfully receive the data and could proceed to the next step.

Am i doing something wrong here?

thanks a lot man

via Semmi Verian