how to place a bitforex api buy order
I don't believe you can"t use the $() syntax to concatanate strings in node.

var message = `https://api.bitforex.com/api/v1/trade/placeOrder?accessKey=   ${accessKey} &lt;--  &amp;amount=  ${amount} &lt;-- &amp;nonce=${nonce} and beyond[...]`


you can simply do 
message = "/api/blahblah" + accessKey

You obviously did this multiple times.  If the issue is something different I will return to the question but this seems simple.