How to .push() each worker's result into an array in node js?

I crushed onto a wall pretty violently. The thing is that I am calling a function in the main thread with the form:

const {StaticPool} = require("node-worker-threads-pool");

const friendsTableWorkers = (result) => {

    const pool = new StaticPool({
        size: 8,
        task: "./worker.js",
        workerData: result
    })

    const nums = [23, 25]
    let buffer = []

    const size = Int32Array.BYTES_PER_ELEMENT*nums.length
    const sharedBuffer = new SharedArrayBuffer(size)
    const sharedArray = new Int32Array(sharedBuffer)

    nums.forEach((num, index) => {
        Atomics.store(sharedArray, index, num);
    })

    pool.exec(sharedArray).then(res => {
        buffer.push( res )
    }).finally(()=>{
        console.log( buffer )
    })

    return buffer 
}

which, in turn, use a fixed pool of workers of the form:

const { parentPort, workerData } = require("worker_threads")
const _ = require('lodash')
const { idToEnsembl } = require('./supportFunctionsBackend.js')

function friendSeeker(n) {  
  console.log(n)
  let res = workerData.map(x => x._doc)
  return {
          ensemblGeneId: idToEnsembl(n),
          nodeidentifier: n,
          geneSetFriends: _.countBy(res, (o) => {
                                      return (o.nodes.includes(n))
                                    }).true}
}
 
parentPort.on("message", (param) => {

  param.forEach( friend => {
    if (typeof friend !== "number") {
      throw new Error("param must be a number.");
    }
    const result = friendSeeker(friend);
    parentPort.postMessage(result);

  })

})

But, when I run it, I get the following:

23
[
  {
ensemblGeneId: 'ENSG00000000003',
nodeidentifier: 23,
geneSetFriends: 2249
  }
]
25

When the real result should be:

[
  {
ensemblGeneId: 'ENSG00000000003',
nodeidentifier: 23,
geneSetFriends: 2249
  },
  {
ensemblGeneId: 'ENSG00000000005',
nodeidentifier: 25,
geneSetFriends: 321
  }
]

or

[
  {
ensemblGeneId: 'ENSG00000000005',
nodeidentifier: 25,
geneSetFriends: 321
  },
  {
ensemblGeneId: 'ENSG00000000003',
nodeidentifier: 23,
geneSetFriends: 2249
  }
]

Which means that just one worker is pushing his result into the buffer array. My question is, then, how can I make all the workers push their result into the buffer array? The order is not important.

Thank you very much in advance