如何解决reactjs函数中的第二个参数未定义
我一直在做一个小项目，以熟悉ReactJS，到目前为止，我玩得很开心。到目前为止，我遇到了一些问题，需要我们的帮助才能解决。
当前，我正在根据授权用户的角色来更改标题中的链接。在我尝试注册用户之前，该部分似乎工作正常。我遇到一个问题，其中props.firebase行代码未定义。我需要做什么才能使它变得不确定？当我删除{authUser}参数时，一切似乎都正常，但是将其添加到函数中时会出现问题。注册文件的代码如下：
import {Link as RouterLink,withRouter} from 'react-router-dom'
import {compose} from 'recompose';
import {withFirebase} from '../../components/Firebase'
import * as ROUTES from '../../constants/routes'
import Avatar from '@material-ui/core/Avatar';
import Button from '@material-ui/core/Button';
import CssBaseline from '@material-ui/core/CssBaseline';
import TextField from '@material-ui/core/TextField';
import Link from '@material-ui/core/Link';
import Grid from '@material-ui/core/Grid';
import Box from '@material-ui/core/Box';
import LockOutlinedIcon from '@material-ui/icons/LockOutlined';
import Typography from '@material-ui/core/Typography';
import {makeStyles} from '@material-ui/core/styles';
import Container from '@material-ui/core/Container';
import SignInPage,{SignInLink} from "../SignInPage";
import styles from '../../assets/jss/website-template/views/signUpPage';
import Header from '../../components/Header/Header';
import HeaderLinks from '../../components/Header/HeaderLinks';
import image from '../../assets/img/kissing.JPG';
import Paper from '@material-ui/core/Paper';
import AuthUserContext from '../../components/Session/context';
function copyright() {
return (
<Typography variant="body2" color="textSecondary" align="center">
{'copyright © '}
<Link color="inherit" href="https://material-ui.com/">
Your Website
</Link>{' '}
{new Date().getFullYear()}
{'.'}
</Typography>
);
}
const useStyles = makeStyles(styles);
const SignUpPage = () => (
<div>
<AuthUserContext.Consumer>
{authUser => authUser === null ?
<SignUpForm authUser={null} /> :
<SignUpForm authUser={authUser} /> }
</AuthUserContext.Consumer>
</div>
);
const SignUpFormBase = ({authUser},props) => {
const classes = useStyles();
const [username,setUsername] = useState('');
const [email,setEmail] = useState('');
const [passwordOne,setPasswordOne] = useState('');
const [passwordTwo,setPasswordTwo] = useState('');
const [inviteCode,setInviteCode] = useState('');
const [error,setError] = useState(null);
const {...rest} = props;
const isInvalid =
passwordOne !== passwordTwo ||
passwordOne === '' ||
email === '' ||
username === '';
const doSubmit = event => {
props.firebase
.checkInviteCode(inviteCode)
.then(role => {
props.firebase
.docreateuserWithEmailAndPassword(email,passwordOne)
.then(authUser => {
return props.firebase
.user(authUser.user.uid)
.set({
username,email,role,});
})
.then(authUser => {
setUsername(username);
setPasswordOne(passwordOne);
setPasswordTwo(passwordTwo);
setEmail(email);
setInviteCode(inviteCode);
props.history.push(ROUTES.HOME);
})
.catch(error => {
setError(error);
});
})
.catch(error => {
console.log(error);
});
event.preventDefault();
}
return (
<div>
<Header
absolute
color="transparent"
brand="Material Kit React"
rightLinks={<HeaderLinks authUser={authUser}/>}
{...rest}
/>
<div
className={classes.pageHeader}
style={{
backgroundImage: "url(" + image + ")",backgroundSize: "cover",backgroundPosition: "top center"
}}
>
<Grid component="main" className={classes.container}>
<CssBaseline/>
<Grid item component={Paper} xs={12} sm={12} md={4}>
<div className={classes.paper}>
<Avatar className={classes.avatar}>
<LockOutlinedIcon/>
</Avatar>
<Typography component="h1" variant="h5">
Sign up
</Typography>
<form className={classes.form} novalidate onSubmit={doSubmit}>
<TextField
margin="normal"
autoComplete="fname"
name="username"
variant="outlined"
required
fullWidth
id="username"
label="Username"
autoFocus
value={username}
onChange={event => setUsername(event.target.value)}
/>
<TextField
margin="normal"
variant="outlined"
required
fullWidth
id="email"
label="Email Address"
name="email"
autoComplete="email"
value={email}
onChange={event => setEmail(event.target.value)}
/>
<TextField
margin="normal"
variant="outlined"
required
fullWidth
name="password"
label="Password"
type="password"
id="password"
autoComplete="current-password"
value={passwordOne}
onChange={event => setPasswordOne(event.target.value)}
/>
<TextField
margin="normal"
variant="outlined"
required
fullWidth
name="password"
label="Confirm Password"
type="password"
id="password"
autoComplete="confirm-password"
value={passwordTwo}
onChange={event => setPasswordTwo(event.target.value)}
/>
<TextField
margin="normal"
variant="outlined"
required
fullWidth
name="inviteCode"
label="InviteCode"
id="inviteCode"
autoComplete="inviteCode"
value={inviteCode}
onChange={event => setInviteCode(event.target.value)}
/>
<Button
type="submit"
fullWidth
variant="contained"
className={classes.submit}
disabled={isInvalid}
>
Sign Up
</Button>
{error && <p>{error.message}</p>}
<Grid container>
<Grid item>
<SignInLink href="#" variant="body2"/>
</Grid>
</Grid>
<Box mt={2}>
<copyright/>
</Box>
</form>
</div>
</Grid>
</Grid>
</div>
</div>
);
}
const SignUpLink = () => (
<p>
<RouterLink to={ROUTES.SIGN_UP}>Don't have an account? Sign Up</RouterLink>
</p>
);
const SignUpForm = compose(
withFirebase,withRouter,)(SignUpFormBase);
export default SignUpPage;
export {SignUpForm,SignUpLink};
正如我所提到的，问题在于props.firebase未定义，因此找不到checkInviteCodes()函数。
解决方法
道具始终是第一个参数，基于功能的组件的正确签名为Component(props)
更改此内容
const SignUpFormBase = ({authUser},props) => {
...
收件人：
const SignUpFormBase = ({authUser,firebase}) => {
...
或
const SignUpFormBase = (props) => {
...
，将authUser和firebase称为props.authUser和props.firebase
您先前的解决方案const SignUpFormBase = ({authUser},props) => {分解道具并将其authUser分配给同名的局部变量。第二个参数（以及以后的其他参数）只是undefined。
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