Promises em paralelo

index.js

const { Runner } = require("./runner");

function funcaoPromise(texto, index) {
    const minhaPromise = new Promise((resolve, reject) => {
        setTimeout(() => {
            resolve(texto+": "+index);
        }, 3000);
    });
    return minhaPromise;
}

async function main() {

    const runner = new Runner(funcaoPromise);

    for(let i = 0; i < 50; i++) {
        runner.addExecution('oi', i);
    }

    await runner.run(25, function(result) { console.log(result)}, function(err) { console.log(err)});

    console.log("FIMMMMMM");

}

main();

Runner.js

/**
Original Author: Caíque Araújo Spósito @kiqaps
Refactoring: Marcelo M. Fleury @marcelomf
*/
class Runner {
	
	constructor(functionPromise) {
		this.functionPromise = functionPromise;
	}

	_executions = []
	stop = false
  
	stopRunner() {
	  this.stop = true
	}
  
	addExecution(...args) {
		this._executions.push(args)
	}
  
	executionCount() { 
		return this._executions.length 
	} 
  
	async run(groupedBy, onResolve, onReject) {
	  if (!groupedBy || groupedBy <= 0) {
		groupedBy = 1
	  }
  
	  while (this._executions.length > 0 && !this.stop) {
		const currentPromises = []
		const currentArgs = this._executions.splice(0, groupedBy)
  
		// eslint-disable-next-line no-unused-vars
		for (let args of currentArgs) {
		  currentPromises.push(this.functionPromise(...args).then(onResolve, onReject))
		}
  
		await Promise.all(currentPromises)
	  }
  
	  return true
	}
}