parse-server analytics alternative, which simply add `.metric(key,value)` function to Parse Objects.

example.js

var id = '2m9fUAIFN3'
new Parse.Query("MyClass")
.get(id)
.then( (o) => {
    o.metric( 'impressions', 1) // updates metric
    o.metric( 'impressions', 1) // but does not
    o.metric( 'impressions', 1) // save immediately
    o.metric( 'impressions', 1) // to prevent race conditions
})

setTimeout( () => {
    new Parse.Query("MyClass")
    .get(id)
    .then( (o) => {
        console.log("get current value")
        console.log( o.get('impressions') )
    })
},5000)

// output: 
//   lazy save
//   4

metricize.js

/*
 * this adds metric(key,amount) function
 * which allows ParseObjects to increment numbers
 * in a parallel way, with a lazy (deferred) save to db
 */
let metricize = function(ParseObject,ttl){
    Parse.Object.extend( ParseObject, {
        metricTTL: ttl,
        metric: function(key, amount){
            this._queue = this._queue || []
            clearTimeout( this._queue.to )
            this._queue.push({key, amount})
            this._queue.to = setTimeout( async () => {
                this._queue.map( (o) => {
                    console.dir({
                        key:    o.key,
                        value:  this.get(o.key),
                        amount: o.amount
                    })
                    this.set(o.key, ( this.get(o.key) || 0 ) + o.amount )
                })
                console.log("lazy save")
                await this.save()
            }, this.metricTTL )
        }
    })
}

metricize("MyClass",2000) // adds MyClass.metric() function