Postman - How to run javascript utility as a pre-step before running the collection

Question

My requirement As a pre-step before running the Postman Collection,

• Want to run javascript utility which creates input BODY data in JSON file
• Using the above JSON file run another utility to create expected JSON file
• Suggestions on using JSON file in BODY to hit POST request

Looking for solution on how to call my javascript utilities everytime before running the collection

This will enable my POSTMAN tests to run seamlessly and will void data dependency

Any views on the above thought are also welcome

Answer 1

Solution suggested by a colleague

• This can be achieved through pre-request script to generate data and store in environment variables.
• Read those variables to build expected data and use in tests for assertion