Implement expression to escape JSON

[AYesman]

Is your feature request related to a problem? Please describe.
using in request body the following construction:

Given request body:
{
"query":" {
    cores
    { archivedDate }
    }"
}

leads to error message:

{
  "statusCode": 400,
  "message": "Unexpected token \n in JSON at position 13",
  "error": "Bad Request"
}

Workaround is to write request body in a single line, which is inappropriate for big queries

Describe the solution you'd like
Add expression to escape all chars from variable/string

Describe alternatives you've considered
to write request body in a single line