writeToDisk.js

const newman = require('newman');

newman.run({
    collection: require('./postman_collection.json'),
    reporters: 'cli'
}).on('start', function (error, args) { // on start of run, log to console
    console.log('Running a collection...');
}).on('request', function (error, execution) {
    if (error) {
        console.error('collection run encountered an error.');
        console.error(error);
    }
    else {
        console.log(execution.response.stream.toString());
    }
});