Converting class to function React Error invalid hook call

Question

I have been converting my class components to functions but I'm stuck on this hook error to do with my export default. I'm sure it's something simple, but I can't find the answer I'm looking for.

This is the code causing the error:

import React from 'react'
import {AppBar, Toolbar, Button, Typography, makeStyles} from '@material-ui/core'
import { connect } from 'react-redux'
import { Link } from 'react-router-dom'
import Menu from './Menu'

const useStyles = makeStyles((theme) => ({
    header: {
        backgroundColor: "#1d3834",

    },
    root: {
      flexGrow: 1,
    },
    menuButton: {
      marginRight: theme.spacing(2),
    },
    title: {
      flexGrow: 1,
    },
  }))

function Header(props) {
    const classes = useStyles()

    const renderContent = () => {
        switch (props.auth) {
            case null:
                return
            case false:
                return (                  
                    <Button color="inherit" href="/signin">Sign In</Button>
                )
            default: 
                return  (
                    <Button color="inherit" href="/api/logout">Sign Out</Button>
                )
        }
    }
    
     return(
        <div className={classes.root}>
        <AppBar position="static" className={classes.header}>
            <Toolbar>
            <Menu/>
            <Typography variant="h6" className={classes.title} >
            <Link 
                to={props.auth ? '/items' : '/'} 
                className="left brand-logo"
            >
                
            </Link>
            </Typography>
                {renderContent()}
            </Toolbar>
        </AppBar>   
        </div>    
     );
    
}

function mapStateToProps({auth}) {
    return{ auth }
}

export default connect(mapStateToProps)(makeStyles(useStyles) (Header))

I'm hoping someone has ran into a similar issue before and would be able to give me some feedback, Thanks :)

Answer 1

The main issue is how you export your component. Try instead as the following:

export default connect(mapStateToProps)(Header)

You don't really need the makeStyles(useStyles) part there.

---

+1 suggestion - not related to the question:

This suggestion is not related to the question itself, it's just a small improvement how I like to organize makeStyles stuff in my code repository with Material-UI .

Usually I create a styles.tsx which would look like in your case as the following, placed next to your component file:

import { makeStyles } from "@material-ui/core"

const useStyles = makeStyles((theme) => ({
    header: {
        backgroundColor: "#1d3834",
    },
    root: {
      flexGrow: 1,
    },
    menuButton: {
      marginRight: theme.spacing(2),
    },
    title: {
      flexGrow: 1,
    },
}))

export default useStyles

Then import in the component as the following:

import useStyles from "./styles"

And the usage similarly as in your component:

function Header(props) {
    const classes = useStyles()

    // ... rest of your component
}