JSFiddle - React, Tailwind, and code Playground

by Iván Pereira

JavaScript

var rfinOu=[
       { "pid": 34, "ava": 30 },
       { "pid": 45, "ava": 30 },
       { "pid": 32, "ava": 60 },
       { "pid": 33, "ava": 30 },
       { "pid": 10, "ava": 61 },
       { "pid": 90, "ava": 60 }
      ];
      
var final = [];
var indexes = {};
var position;

rfinOu.forEach(function(item){

	if( indexes.hasOwnProperty(item.ava) ){
  
  	final[indexes[item.ava]].count++;
    final[indexes[item.ava]].Pids.push(item.pid);
  
  }else{
  
  	position = final.length;
  
  	indexes[item.ava] = position;
    
    final[position] = {ava: item.ava, count: 1};
    final[position].Pids = [item.pid]; 
  
  }

});

console.log(JSON.stringify(final));