How to save response file every iterationData in newman librarty

Hallo I want to save file response every iterationData in newman library node js.
In collection I have one request. This is my file.

const newman = require('newman');
const fs = require('fs');
      let today = new Date().toISOString().slice(0, 10)
      let time = Date.now();
      let jsonFile = './response.json'
newman.run({
    collection: require('./collection.json'),
    reporters: 'cli',
    iterationData: jsonFile,
    verbose: true
}).on('request', function (error, data) {
    if (error) {
        console.error(error);
        return; 
    }
    const requestname = data.item.name; 
    const filename = 'response_'+requestname+ '_' + today + '_' + time+'.json'; 
    const content  = data.response.json(); 
    fs.writeFile(filename, JSON.stringify(content), function (error) {
        if (error) { 
            console.error(error);
        }
    });
console.log('Request name: ' + data.item.name);
        });