I'm trying to use semantic UI for React with its modal.
Dropdown is ok but modal can't load :
import {DropDown} from "semantic-ui-react";
import {Modal} from "semantic-ui-react";
export default class Builder extends Component {
render(){
return(
<DropDown/>
<Modal/>
)
}
}
The console is returning this error :
app.js:547 Warning: React.createElement: type is invalid -- expected a string
(for built-in components) or a class/function (for composite components) but got: undefined
You likely forgot to export your component from the file it's defined in.
Check the render method of `Portal`.
I have already tried like this :
import Modal from "semantic-ui-react";
And as I saw, Modal folder is at the same level as the Dropdown in my packages.
Any help would be welcome!
Thanks
I think the solution to your problem is either of the following:
You forgot to import import React, { Component } from "react";
The structure of your code. You must wrap both JSX elements in an enclosing tag as they are adjacent. It should be like this:
<div>
<Dropdown/>
<Modal/>
</div>
You don't have to separate import two components as they are both in semantic-ui-react library.
Hope this helps
Related
I have a draggable component in my project, but it throws an error whenever I start the dev server -
react-jsx-dev-runtime.development.js:87 Warning: React.jsx: type is invalid -- expected a string (for built-in components) or a class/function (for composite components) but got: undefined. You likely forgot to export your component from the file it's defined in, or you might have mixed up default and named imports.
Check your code at draggable.js:9.
Here is my code for draggable.js:
import React, { Component } from "react";
import ReactDOM from 'react-dom';
import { Draggable } from "react-draggable";
console.log(Draggable); //undefined
export class Board extends Component {
render() {
return (
<div>
<Draggable position={{ x: 0, y: 0 }} handle=".handle">
<div>
<div className="handle">Drag me</div>
<div>I will move with the handle</div>
</div>
</Draggable>
</div>
);
}
}
Using the console.log statement I have found that the problem is the Draggable component on line 9 is undefined. But after reading the documentation for react-draggable I can't figure out why that is.
I ran npm install react-draggable and checked package.json. The project has react-draggable version 4.4.5 installed
The solution was to change the import statement
import { Draggable } from "react-draggable";
to
import Draggable from "react-draggable";
Note that DraggableCore import statement goes in curly brackets, that was the cause of my confusion
Within my React application, I'm met with an issue which seems to be related to imports or extending Component | React.Component with my main App class.
The error I'm met with is:
Element type is invalid: expected a string (for built-in components)
or a class/function (for composite components) but got: undefined.
I assumed it might have to do with default vs named import of Component, but even when using React.Component instead of Component, I'm met with this issue.
Is there any reason why this would occur?
The import statements I've used are structure as such, below:
import React from 'react';
import Component from 'react';
import './App.css';
import Exercises from "./components/ExerciseDay";
import MySurvey from "./components/MySurvey";
import ExerciseSelector from "./components/ExerciseSelector";
import ToggleDisplay from 'react-toggle-display';
export default class App extends React.Component {
render() {
const surveyCompleted = localStorage.getItem("experience");
return (
<div className="App">
<header className="App-header">
<h1 className="App-title" style={{fontFamily: "Comfortaa, cursive", fontSize: 35}}>
Sheiko Workout Finder
</h1>
</header>
<ToggleDisplay show={!surveyCompleted} tag="section">
<MySurvey/>
</ToggleDisplay>
<ToggleDisplay show={surveyCompleted !== null}>
<ExerciseSelector/>
<Exercises/>
</ToggleDisplay>
<footer style={{fontFamily: "Comfortaa, cursive", fontSize: 20}}>
<p>
Note here -
</p>
</footer>
</div>
);
}
}
A Component is named export. Instead of import Component from 'react';
it should be import { Component } from 'react'; //with curly braces
But you are not using it. It can be deleted because you are using React.Component.
Most likely there is another problem because there is not shown how you are exporting other components from other files ( ExerciseDay,MySurvey,ExerciseSelector ) they or something from them might be named export instead of default export. Check how you are exporting them
And there is another case that will cause this error. If you are importing something wrong also in these components. For example, something imported in ExerciseDay from another file is incorrect. Like exported as named export instead of default export or vice versa
I am trying to add a search bar within a navbar using react-bulma-components, but I get this error:
Error: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined. You likely forgot to export your component from the file it's defined in, or you might have mixed up default and named imports.
Check the render method of TopNav.
I don't get the error when I exclude the Navbar.Item containing a Field element. The following is my code:
<Navbar>
<Navbar.Brand>
<Navbar.Item renderAs="a" href="/">
The Nomad
</Navbar.Item>
<Navbar.Burger>
</Navbar.Burger>
</Navbar.Brand>
<Navbar.Item>
<Field>
<Control>
<Input placeholder="Search" />
</Control>
</Field>
</Navbar.Item>
</Navbar>
Any help is much appreciated!
I managed to figure this out on my own. It turns out that Field, Control and Input are properties of the Form component. I had the following in my import statements (incorrect version):
import React from 'react';
import { Navbar } from 'react-bulma-components';
import { Field, Control, Input } from 'react-bulma-components';
What I should have had was this:
import React from 'react';
import { Navbar } from 'react-bulma-components';
import { Form } from 'react-bulma-components';
const { Field, Control, Input } = Form;
I'm getting an error whenever I try to render a Field from Redux-form-material-ui. This is my form code:
import React, { Component } from 'react';
import { Field, reduxForm } from 'redux-form';
import { TextField, DatePicker, SelectField } from 'redux-form-material-ui';
class InputForm extends Component {
render() {
return(
<form>
<div>
<Field name="eventDate" component={DatePicker} format={null} hintText="What day is the event?"/>
</div>
</form>
)
}
}
InputForm = reduxForm({
form: 'contact'
})(InputForm);
export default InputForm;
The error that I'm getting is this one:
Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined. You likely forgot to export your component from the file it's defined in, or you might have mixed up default and named imports.
Check the render method of ConnectedField.
I know it has to do with the component={ DatePicker } assigned on the Field element because if I change it to TextFIeld it renders okey.
I found out that DatePicker hasnt been implemented(do not know why) on the new release of redux-form-material-ui#next. So this has been solved.
I'm playing around with React and ES6 using babel and webpack. I want to build several components in different files, import in a single file and bundle them up with webpack
Let's say I have a few components like this:
my-navbar.jsx
import React from 'react';
import Navbar from 'react-bootstrap/lib/Navbar';
export class MyNavbar extends React.Component {
render(){
return (
<Navbar className="navbar-dark" fluid>
...
</Navbar>
);
}
}
main-page.jsx
import React from 'react';
import ReactDOM from 'react-dom';
import MyNavbar from './comp/my-navbar.jsx';
export class MyPage extends React.Component{
render(){
return(
<MyNavbar />
...
);
}
}
ReactDOM.render(
<MyPage />,
document.getElementById('container')
);
Using webpack and following their tutorial, I have main.js:
import MyPage from './main-page.jsx';
After building the project and running it, I get the following error in my browser console:
Error: Invariant Violation: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined. Check the render method of `MyPage`.
What am I doing wrong? How can I properly import and export my components?
Try defaulting the exports in your components:
import React from 'react';
import Navbar from 'react-bootstrap/lib/Navbar';
export default class MyNavbar extends React.Component {
render(){
return (
<Navbar className="navbar-dark" fluid>
...
</Navbar>
);
}
}
by using default you express that's going to be member in that module which would be imported if no specific member name is provided. You could also express you want to import the specific member called MyNavbar by doing so: import {MyNavbar} from './comp/my-navbar.jsx'; in this case, no default is needed
Wrapping components with braces if no default exports:
import {MyNavbar} from './comp/my-navbar.jsx';
or import multiple components from single module file
import {MyNavbar1, MyNavbar2} from './module';
To export a single component in ES6, you can use export default as follows:
class MyClass extends Component {
...
}
export default MyClass;
And now you use the following syntax to import that module:
import MyClass from './MyClass.react'
If you are looking to export multiple components from a single file the declaration would look something like this:
export class MyClass1 extends Component {
...
}
export class MyClass2 extends Component {
...
}
And now you can use the following syntax to import those files:
import {MyClass1, MyClass2} from './MyClass.react'
MDN has really nice documentation for all the new ways to import and export modules is ES 6 Import-MDN . A brief description of it in regards to your question you could've either:
Declared the component you were exporting as the 'default' component that this module was exporting:
export default class MyNavbar extends React.Component { , and so when Importing your 'MyNavbar' you DON'T have to put curly braces around it : import MyNavbar from './comp/my-navbar.jsx';.
Not putting curly braces around an import though is telling the document that this component was declared as an 'export default'. If it wasn't you'll get an error (as you did).
If you didn't want to declare your 'MyNavbar' as a default export when exporting it : export class MyNavbar extends React.Component { , then you would have to wrap your import of 'MyNavbar in curly braces:
import {MyNavbar} from './comp/my-navbar.jsx';
I think that since you only had one component in your './comp/my-navbar.jsx' file it's cool to make it the default export. If you'd had more components like MyNavbar1, MyNavbar2, MyNavbar3 then I wouldn't make either or them a default and to import selected components of a module when the module hasn't declared any one thing a default you can use: import {foo, bar} from "my-module"; where foo and bar are multiple members of your module.
Definitely read the MDN doc it has good examples for the syntax. Hopefully this helps with a little more of an explanation for anyone that's looking to toy with ES 6 and component import/exports in React.
I Hope this is Helpfull
Step 1: App.js is (main module) import the Login Module
import React, { Component } from 'react';
import './App.css';
import Login from './login/login';
class App extends Component {
render() {
return (
<Login />
);
}
}
export default App;
Step 2: Create Login Folder and create login.js file and customize your needs it automatically render to App.js Example Login.js
import React, { Component } from 'react';
import '../login/login.css';
class Login extends Component {
render() {
return (
<div className="App">
<header className="App-header">
<h1 className="App-title">Welcome to React</h1>
</header>
<p className="App-intro">
To get started, edit <code>src/App.js</code> and save to reload.
</p>
</div>
);
}
}
export default Login;
There are two different ways of importing components in react and the recommended way is component way
Library way(not recommended)
Component way(recommended)
PFB detail explanation
Library way of importing
import { Button } from 'react-bootstrap';
import { FlatButton } from 'material-ui';
This is nice and handy but it does not only bundles Button and FlatButton (and their dependencies) but the whole libraries.
Component way of importing
One way to alleviate it is to try to only import or require what is needed, lets say the component way. Using the same example:
import Button from 'react-bootstrap/lib/Button';
import FlatButton from 'material-ui/lib/flat-button';
This will only bundle Button, FlatButton and their respective dependencies. But not the whole library. So I would try to get rid of all your library imports and use the component way instead.
If you are not using lot of components then it should reduce considerably the size of your bundled file.