steps.ts

import { Given, When, Then } from 'cucumber';
import { act } from 'react-dom/test-utils';

import Element from './path/to/Element';

Given(/I go to (.*)$/, function(link) {
    window.location.hash = `#/${link}`;
});

When(/I click the (\S+) button$/, function(id) {
    const $element = new Element({id});

    element.click(); // <- this method already wraps the click inside of act for you.
});

Then(/the (\S+) button is (visible|not visible)$/, function(name, state) {
    const $element = new Element({id});
    
    expect($element.isInDom())
        .toEqual(state === 'visible')
});