Writing 2 plugins refering to the same bunch of code

Thanks. What is the syntax for this ?
I used this documentation https://doc.qt.io/qt-5/qtqml-javascript-imports.html

import QtQuick 2.9
import QtQuick.Controls 2.2 //1.4 
import MuseScore 3.0
//import "file:///D:/data/MuseScore3/Plugins/testlib.js" as TestLib
import "testlib.js" as TestLib
MuseScore {
      menuPath: "Plugins.pluginName"
      description: "Description goes here"
      version: "1.0"
      pluginType : "dialog"
      width: 800
      height: 500
     }

With a really basic teslib.js file:

function GiveHelloText() { return "hello"; }

And it returns the following error:

   ligne 4 : Script file:///D:/data/MuseScore3/Plugins/testlib.js unavailable
   ligne 1 : Expected token `;'
   ligne 1 : Expected token `,'

Is this the right syntax ?
BTW, I used to have a link to the versions of the different QML components that were supported in MuseScore. Couldn't find a back. Can someone point me back to that page ?