//1334461/js/formBuilder.js
export default class Form {
    constructor() {
        this.dataset = readSettings();
    }
    readSettings() {
        let vm = this
        // http://localhost:8080
        fetch('json/symbols.json').then((response) => response.json()).then(json => {
            let symbols = Object.entries(json);
            console.log(typeof symbols);
            return symbols;
        }).catch(function () {
            vm.dataError = true
        });
    }
//.......................................и так далее
}

//1334461/index.js
import Form from './js/formBuilder.js';
window.builder = Form;

//1334461/index.htm
<script type="module" src="index.js"></script>
321