Customizing the Request format in Postman

I have something like this in my Pre-Request script in postman
var newData = data;

var str = JSON.stringify(newData);
str= str.replace(/~/g,"");
str= str.replace(/|/g,",");
str= str.replace(/’/g,""");
str= str.replace(/"[/g,"[");
str= str.replace(/]"/g,"]");

pm.environment.set(‘request’, str);

In body I have defined like this,
{{request}}

I am executing the test runner, there I am passing the csv file, from there each row is fetched and appropriate json request is made,
but in the request it also sending the unwanted data, like the ip_port, url, which is passed to set in postman environment, I dont want that to come in my request,

So what I tried:

  1. tried to remove from the data itself i.e str.remove, but this results in removing the content from main data as well,
    so how to implement the same via using the map, so i can easily remove and send only the needed fields,
    how to do something like this?