Most components ship with Component / Foundation classes which are used to provide a full-fidelity Material Design component. Depending on what technology you use in your stack, there are several ways to import the JavaScript.
import {MDCFoo, MDCFooFoundation} from '@material/foo';
const mdcFoo = require('mdc-foo');
const MDCFoo = mdcFoo.MDCFoo;
const MDCFooFoundation = mdcFoo.MDCFooFoundation;
require(['path/to/mdc-foo'], mdcFoo => {
const MDCFoo = mdcFoo.MDCFoo;
const MDCFooFoundation = mdcFoo.MDCFooFoundation;
});
const MDCFoo = mdc.foo.MDCFoo;
const MDCFooFoundation = mdc.foo.MDCFooFoundation;
mdc.foo.MDCFoo.attachTo(document.querySelector('.mdc-foo'));
import {MDCFoo} from '@material/foo';
const foo = new MDCFoo(document.querySelector('.mdc-foo'));