This will run a remote script on InDesign. It curls the script and then executes it.

local_script_for_running_remote_script_on_indesign.jsx

////////////////////////////////////////////////////////////
// For InDesign Windows !!!!!                             //
// See https://forums.adobe.com/message/10632451#10632451 //
// By Trevor http://creative-scripts.com                  //
////////////////////////////////////////////////////////////


var remoteCodeUrl, vbs, appleScript, remoteScript;

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Change to desired URL, must be raw, i.e. no HTML, can use github / patesbin to host make sure to include the /raw part in the link //
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
remoteCodeUrl = 'https://gist.githubusercontent.com/Trevor-/a297b25e270c2e19d3ba12b5406212d9/raw';


if ($.os[0] === 'M') { // [M]ac
    appleScript = "do shell script \"curl 'remoteCodeUrl'\"".replace("remoteCodeUrl", remoteCodeUrl);
    remoteScript = app.doScript(appleScript, ScriptLanguage.APPLESCRIPT_LANGUAGE);

} else { // [W]indows
    vbs = [
        // Create Shell Object
        'Set shell = CreateObject("WScript.Shell")',
        // Execute curl in powershell
        'Set executor = shell.Exec("powershell.exe  -windowstyle hidden Invoke-WebRequest -Uri remoteCodeUrl | Select-Object -ExpandProperty Content")'.replace("remoteCodeUrl", remoteCodeUrl),
        // Capture stdout
        'executor.StdIn.Close',
        // "Forward" result to jsx engine
        'returnValue = executor.StdOut.ReadAll',
    ].join('\n');
    remoteScript = app.doScript(vbs, ScriptLanguage.VISUAL_BASIC);
}

/////////////////////////////////////
// Change as per remoteScript      //
// This works for the URL provided //
/////////////////////////////////////

// Set script args
app.scriptArgs.setValue("scriptArg1", "Hello");
// Set environmental vars
$.setenv("envVar1", "World");
// Run the "remote" script
app.doScript(remoteScript, ScriptLanguage.JAVASCRIPT);
// Share functions and vars
// "blah" and "testVar" are grabbed from the remote script
blah('Demo by: ', testVar);


/* Some sources
https://github.com/PowerShell/PowerShell/issues/3028
https://stackoverflow.com/questions/36941027/how-to-return-powershell-variable-to-vbscript
https://forums.adobe.com/thread/2000455
*/