app.js

var doTask = (taskName) => {
    var begin=Date.now();
    return new Promise(function(resolve,reject){
    setTimeout(function(){
    var end= Date.now();
    var timeSpent=(end-begin)+ "ms";
    console.log('\x1b[36m', "[TASK] FINISHED: " + taskName + " in " +
    timeSpent ,'\x1b[0m');
    resolve(true);
    },(Math.random()*200));
    });
    }

async function init() { numberOfTasks = 20;
const concurrencyMax = 2;
const taskList = [...Array(numberOfTasks)].map(() => [...Array(~~(Math.random() * 10 + 3))].map(() =>
String.fromCharCode(Math.random() * (123 - 97) + 97) ).join('') )
const counter = 0;
const concurrencyCurrent = 0
console.log("[init] Concurrency Algo Testing...") 
console.log("[init] Tasks to process: ", taskList.length) 
console.log("[init] Task list: " + taskList) 
console.log("[init] Maximum Concurrency: ", concurrencyMax,"\n")
await manageConcurrency(taskList,counter,concurrencyMax,concurrencyCurrent); }




  
async function manageConcurrency(taskList, counter, concurrencyMax, concurrencyCurrent) {
  while (counter < taskList.length) {
    while (concurrencyCurrent < concurrencyMax && counter < taskList.length) {
      
      const task = doTask(taskList[counter]);
      concurrencyCurrent++;
     
      console.log("[EXE] CONCURRENCY " +concurrencyCurrent + " OF  "+ concurrencyMax) 
      var c2=counter+1;
      console.log(" [EXE] Task COUNT "+ c2 +" OF "+ taskList.length)
      console.log( "[TASK] STARTED: " + taskList[counter] );
      counter++;
      
      task.then(() => {
        concurrencyCurrent--;
      });
    }
   await new Promise(resolve=> setTimeout(resolve));
  }
}



init();