dwysokinski.me/src/components/Layout/Navbar.js

import React from 'react';
import { graphql, useStaticQuery } from 'gatsby';
import classnames from 'classnames';
import { ROUTE } from '@config/routing';
import smoothScroll from '@utils/smoothScroll';
import { HEADER_ID } from '@features/IndexPage/components/Header/Header';
import { SECTION_ID as PORTFOLIO_SECTION_ID } from '@features/IndexPage/components/Portfolio/Portfolio';
import { SECTION_ID as CONTACT_SECTION_ID } from '@features/IndexPage/components/Contact';

import { makeStyles } from '@material-ui/core/styles';
import { AppBar, Toolbar, Container, Link } from '@material-ui/core';
import { Link as GatsbyLink } from 'gatsby-theme-material-ui';

function Navbar({ className, ...rest }) {
  const classes = useStyles();
  const data = useStaticQuery(graphql`
    {
      logo: file(base: { eq: "logo.svg" }) {
        publicURL
      }
    }
  `);

  return (
    <AppBar
      component="nav"
      position="static"
      {...rest}
      className={classnames(classes.appBar, className)}
    >
      <Container>
        <Toolbar className={classes.toolbar} disableGutters>
          <div className={classes.titleContainer}>
            <GatsbyLink
              title="Strona główna"
              color="inherit"
              to={ROUTE.INDEX_PAGE}
            >
              <img
                className={classes.logo}
                src={data.logo.publicURL}
                alt="logo"
              />
            </GatsbyLink>
          </div>
          <div className={classes.divider} />
          <div className={classes.linkContainer}>
            <Link
              title="Start"
              color="inherit"
              href={'#' + HEADER_ID}
              onClick={smoothScroll(HEADER_ID)}
            >
              Start
            </Link>
            <Link
              title="Portfolio"
              color="inherit"
              href={'#' + PORTFOLIO_SECTION_ID}
              onClick={smoothScroll(PORTFOLIO_SECTION_ID)}
            >
              Portfolio
            </Link>
            <Link
              title="Contact"
              color="inherit"
              href={'#' + CONTACT_SECTION_ID}
              onClick={smoothScroll(CONTACT_SECTION_ID)}
            >
              Contact
            </Link>
          </div>
        </Toolbar>
      </Container>
    </AppBar>
  );
}

const useStyles = makeStyles(theme => ({
  appBar: {
    backgroundColor: 'transparent',
    color: '#fff',
    boxShadow: 'none',
  },
  linkContainer: {
    '& > *:not(:last-child)': {
      marginRight: theme.spacing(2),
    },
    [theme.breakpoints.down('xs')]: {
      '& > *:not(:last-child)': {
        marginRight: theme.spacing(1),
      },
    },
  },
  logo: {
    width: '56px',
    height: 'auto',
    [theme.breakpoints.down('xs')]: {
      width: '48px',
    },
  },
  divider: {
    flexGrow: 1,
  },
  link: {
    width: '100%',
  },
  titleContainer: {
    display: 'flex',
    alignItems: 'center',
    '& > *:not(:last-child)': {
      marginRight: theme.spacing(1),
    },
  },
  toolbar: {
    padding: theme.spacing(2, 0),
    fontSize: '1.25rem',
  },
}));

export default Navbar;