node.js - Passing a parameter trough require-module to ES6 class in Nodejs -

i learning use ecmascript6 -styled classes in nodejs (7.7.3). have used kind of programming style:

//app.js  var forecasthandler = require('./forecasthandler.js');    //forecasthandler.js  class forecasthandler {    constructor() {}  }    module.exports = new forecasthandler()

it has worked until now, because have pass parameters module.

//app.js  var forecasthandler = require('./forecasthandler.js')(3600);    //forecasthandler.js  class forecasthandler {    constructor(cacheupdatedelay) {}  }    module.exports = new forecasthandler(cacheupdatedelay)

i got error: referenceerror: cacheupdatedelay not defined. can pass parameter forecasthandler-module using es6 styled classes , creating object @ module.exports? if export class , create object in app.js, code works, it's syntax ugly.

//app.js  var forecasthandlerclass = require('./forecasthandler.js');  var forecasthandler = new forecasthandlerclass(3600);    //forecasthandler.js  module.exports = forecasthandler

edit: better examples

module.exports = new forecasthandler(cacheupdatedelay) 

the trouble code initialises object when code first run.

require('./forecasthandler.js') means "execute code in forecasthandler.js , give me exports object. means js engine tries run new forecasthandler(cacheupdatedelay) when there no cacheupdatedelay created.

the simple way 1 provide. load class, try make new instance of it. if really want one-line it, can in app.js:

var forecasthandler = new (require('./forecasthandler.js'))(3600); 

there various other ways this. simplest involve not exporting class function.

for instance, in module file:

module.exports = cacheupdatedelay => new forecasthandler(cacheupdatedelay); // or module.exports = function(cacheupdatedelay) {     return new forecasthandler(cacheupdatedelay); };