我试图直接从Material Ui(简单菜单https://material-ui.com/demos/menus/#menus)文档中使用此组件,以使菜单出现。但是,我在下面的当前尝试中遇到TypeError: react__WEBPACK_IMPORTED_MODULE_1___default.a.useState is not a function
错误。我尝试过:
import React, { useState } from 'react';
,然后在React
内删除了const [anchorEl, setAnchorEl] = React.useState(null);
,使其看起来像:const [anchorEl, setAnchorEl] = useState(null);
null
,但仍然遇到相同的错误。注意:另一种尝试安装了正确的软件包并使我的package.json
文件看起来像这样(TypeError dispatcher.useState is not a function when using React Hooks):
{
"name": "speedy-react",
"version": "0.1.0",
"private": true,
"dependencies": {
"@material-ui/core": "^3.9.0",
"@material-ui/icons": "^3.0.2",
"classnames": "^2.2.6",
"node-sass": "^4.11.0",
"prop-types": "^15.6.2",
"react": "16.7.0-alpha.0",
"react-dom": "16.7.0-alpha.0",
"react-test-renderer": "16.7.0-alpha.0",
"react-scripts": "2.1.3"
},
"scripts": {
"start": "react-scripts start",
"build": "react-scripts build",
"test": "react-scripts test",
"eject": "react-scripts eject"
},
"eslintConfig": {
"extends": "react-app"
},
"browserslist": [
">0.2%",
"not dead",
"not ie <= 11",
"not op_mini all"
]
}
错误的屏幕截图:
我在做什么错,我该如何解决?
import React from 'react';
import Button from '@material-ui/core/Button';
import Menu from '@material-ui/core/Menu';
import MenuItem from '@material-ui/core/MenuItem';
const SimpleMenu = () => {
const [anchorEl, setAnchorEl] = React.useState(null);
function handleClick(event) {
setAnchorEl(event.currentTarget);
}
function handleClose() {
setAnchorEl(null);
}
return (
<div>
<Button
aria-owns={anchorEl ? 'simple-menu' : undefined}
aria-haspopup="true"
onClick={handleClick}
>
Open Menu
</Button>
<Menu id="simple-menu" anchorEl={anchorEl} open={Boolean(anchorEl)} onClose={handleClose}>
<MenuItem onClick={handleClose}>Profile</MenuItem>
<MenuItem onClick={handleClose}>My account</MenuItem>
<MenuItem onClick={handleClose}>Logout</MenuItem>
</Menu>
</div>
);
};
export default SimpleMenu;
答案 0 :(得分:0)
虽然我不确定上面的代码出了什么问题(我猜是使用非发行版的Material-ui,但据文档说明,导出未默认导出),但对于我来说,发生此错误的原因是不正确的进口。我的问题是我正在尝试
import someNonDefaultFunction from 'someModule';
在命名/非默认导入周围添加括号可以为我解决相同的错误消息:
import {someNonDefaultFunction} from 'someModule';