thunderhub/.storybook/preview.js

import { addDecorator, addParameters } from '@storybook/react';
import themeDecorator from './themeDecorator';
import { withKnobs } from '@storybook/addon-knobs';
import { INITIAL_VIEWPORTS } from '@storybook/addon-viewport';

const customViewports = {
    smallScreen: {
        name: 'Small Screen',
        styles: {
            width: '578px',
            height: '100%',
        },
    },
};

addParameters({
    viewport: {
        viewports: { ...INITIAL_VIEWPORTS, ...customViewports },
    },
});
addDecorator(themeDecorator);
addDecorator(withKnobs);