svelte_demo.svelte

<script>
import {get} from "svelte/store"; 
export const getBalance = (contract) => async (e) => {
    await contract; // ensure $web3.eth is defined
    return get(web3).eth.getBalance(get(selectedAccount));
};
export let checkAccount = get(selectedAccount) || "0x0000000000000000000000000000000000000000";
let myContract = getContext("myContract");
</script>

<h1>
  {await getBalance(myContract)()}
  {:then data}
  Your balance is: {data}
  {/await}
</h1>

<style>
.h1{
  font-size: 1rem;
}
</style>