Getting error when running Postman Script via Newman - node.js

Question

I am trying to run the following Postman Script via Newman to write the response to file:
//verify http response code
pm.test("Report Generated", function () {
pm.response.to.have.status(200);
});
var fs = require('fs');
var outputFilename = 'C:/Users/archit.goyal/Downloads/spaceReport.csv';
fs.writeFileSync(outputFilename, pm.response.text());
The request gives a response but getting the following error when writing to file:
1? TypeError in test-script
┌─────────────────────────┬──────────┬──────────┐
│ │ executed │ failed │
├─────────────────────────┼──────────┼──────────┤
│ iterations │ 1 │ 0 │
├─────────────────────────┼──────────┼──────────┤
│ requests │ 20 │ 0 │
├─────────────────────────┼──────────┼──────────┤
│ test-scripts │ 20 │ 1 │
├─────────────────────────┼──────────┼──────────┤
│ prerequest-scripts │ 0 │ 0 │
├─────────────────────────┼──────────┼──────────┤
│ assertions │ 2 │ 0 │
├─────────────────────────┴──────────┴──────────┤
│ total run duration: 1m 48.3s │
├───────────────────────────────────────────────┤
│ total data received: 1.24MB (approx) │
├───────────────────────────────────────────────┤
│ average response time: 5.3s │
└───────────────────────────────────────────────┘
# failure detail
1. TypeError fs.writeFileSync is not a function
at test-script
inside "3i_BMS_Amortization_Schedule / GetReport"
Please help

Answer 1

Postman itself cannot execute scripts like that. To save your responses of all the api requests, you can create a nodeJS server which will call the api through newman and then save the response to a local file. Here is an example -
var fs = require('fs'),
newman = require('newman'),
allResponse=[],
outputFilename = 'C:/Users/archit.goyal/Downloads/spaceReport.csv';
newman.run({
collection: '//your_collection_name.json',
iterationCount : 1
})
.on('request', function (err, args) {
if (!err) {
//console.log(args); // --> args contain ALL the data newman provides to this script.
var responseBody = args.response.stream,
response = responseBody.toString();
allResponse.push(JSON.parse(response));
}
})
.on('done', function (err, summary) {
fs.writeFile(outputFilename,"");
for(var i =0;i<allResponse.length;i++)
{
fs.appendFileSync(outputFilename,JSON.stringify(allResponse[i],null,5));
}
});
Note that, the above code will save only the responses. Other data like request , or URl can be extracted in a similar manner. To run this, install newman in the same directory as the script, then run the script using -
node file_name.js