Can't I use variable inside of jquery document.getReady function?

constructor( ... ... ) {
ionViewDidLoad() {
    console.log('ionViewDidLoad MainPage');
    $(() => {



I console loged on jquery , but it always says undefined.
(()=>{} is same as (document).ready , I think.

how can I use variable declared on .ts to document.ready inside?

Yap, you can use JQuery in Ionic-4 by declaring $

declare var $

then you can use JQuery like $ sign.

i’m not asking how to use jquery…i’m using it quite well
but wonder how can I use variable used in document.getReady function on jquery

Not clear.
Write code and details.