React fails to some weird error when importing another component. If I remove ChristmasMap references in App.js then app works fine. But I want to import the ChristmasMap. Any help?
App.js
import React, { Component } from 'react';
import './ChristmasMap';
class App extends Component {
render() {
return (
<div>
<p>asd</p>
<ChristmasMap />
</div>
);
}
}
export default App;
ChristmasMap.js
import React, { Component } from 'react';
class ChristmasMap extends Component {
render(){
return (
<div>
component
</div>
);
}
};
export default ChristmasMap;
And the error I'm getting is App.js:56 Uncaught ReferenceError: ChristmasMap is not defined(…)
You should do:
import ChristmasMap from './ChristmasMap'
Related
I am new to react and what to understand why the console.log is called twice when inside of the render function ?
import React, { Component } from "react";
import "./App.css";
class App extends Component {
render() {
console.log("Prints twice in console");
return (
<div className="App">
</div>
);
}
}
export default App;
Where as if i dont extend from component and use function instead the console prints only once
import React from "react";
import "./App.css";
function App() {
console.log("prints once");
return <div className="App"></div>;
}
export default App;
Check your index.js in the ./src directory. I think it renders the App component in
<React.StrictMode>
Remove it and it will stop rendering the function twice.
Also you can check This
I am using React create app and I understand how to import a component into my main app which is called app.js.
What I do not understand is how I import a component in a component which is then imported in app.js (nested component).
In my app.js file, I have a component called Portfolio. In my portfolio.js file, I have a component called Language. Is it even possible to nest components with React create app? Because it does not seem to work.
This is what I tried to do:
In my app.js file :
import React from "react";
import logo from "./logo.svg";
import "./App.css";
import Portfolio from './components/portfolio';
import "./css/styles.css"
function App() {
return (
<div className="App">
<header>
<h1>My beautiful title</h1>
</header>
<Portfolio />
</div>
);
}
export default App;
In my portfolio.js file :
import React, {Component} from 'react';
import Language from './components/language';
class Portfolio extends Component {
render() {
return (
<div className="portfolio">
<Language/>
<h1>My protfolio</h1>
</div>
);
}
}
export default Portfolio;
And in language.js I have:
import React, {Component} from 'react';
class Language extends Component {
render() {
return(
<div>Switch language</div>
);
}
}
export default Language;
In my browser, I keep getting the following error:
"./src/components/portfolio.js Module not found: Can't resolve
'./components/language' in
'C:\Users\mluce\exercice-react\src\components'"
My language.js file is definitely sitting in my components folder. I do not understand why I get this error?
In portfolio.js:
import Language from './language';
I'm new in React Js don't judge me bad for it. I was writing some class to learn but unfortunately I can't export and import one of my class.
import React from "react";
class Yozuvla extends React.Component{
render(){
return(
<div>
<p>Ismingiz</p>
<p>Familyagiz</p>
</div>
);
}
}
export default Yozuvla;
Here is the second class which can't be imported
import React from "react";
import yozuv from "./components/Form";
class App extends React.Component{
render(){
return (
<div>
<yozuv/>
</div>
);
}
}
export default App;
yozuv class don't show up why.browser is white like snow
Classname should be in PascalCase,
import yozuv from "./components/Form";
this should be
import Yozuv from "./components/Form";
Usage
<Yozuv/>
When you add any element like <yozuv/> (starts with small letter), react takes it as a normal HTML tag and NOT a React Component.
import React, { Component } from 'react'
// make sure the location of file is the same for Yozuvla
import Yozuvla from'./components/Form'
class App extends Component {
render() {
return (
<div>
<Yozuvla/>
</div>
)
}
}
export default App;
tell me in commit it work or not
i've a component that i import, but its not displayed on the page.
this is my app.js file. i imported the <player/>component but it is not getting displayed properly on the browser.
import React, { Component } from "react";
import logo from "./logo.svg";
import "./App.css";
import { player } from "./player";
class App extends Component {
render() {
return (
<div className="App">
<div>
<player />
</div>
</div>
);
}
}
export default App;
this is the contents of the player.js
import React from "react";
import { Button } from "evergreen-ui";
export default class player extends React.Component {
constructor(...args) {
super(...args);
this.state = {
shoot: 0
};
}
shoot() {
this.setState.shoot = Math.floor(Math.random() * Math.floor(3));
}
render() {
return (
<div>
<h1>hello there</h1>
<h1>{this.state.shoot}</h1>
<Button onClick={() => this.shoot}>Shoot another
value</Button>
</div>
);
}
}
In your code, you've exported your player component as a default export
export default class player extemds React.Component
But in your import of it in the other file, you're importing it as a named export
import { player } from "./player";
Try importing it without the curly braces as you would with a default export
import player from "./player";
You are doing two mistakes:
1. Importing the component in the wrong way
2. Rendering the component in the wrong way
Solution
The component should be imported without the curly braces
The react component "player" is supposed to start with capital letters i.e. it should be renamed as Player
Below is the working code I have tried in my local machine. It only modifies App.js
import React, { Component } from "react";
import logo from "./logo.svg";
import "./App.css";
import Player from "./player"; // imported without curly braces and with capital first letter
class App extends Component {
render() {
return (
<div className="App">
<div>
<Player /> {/* Rendering the correct way */}
</div>
</div>
);
}
}
export default App;
Sidenote
In player.js, you are setting the state in the wrong fashion, it won't work because:
setState is a method and not a object
this is not binded with method shoot. It will throw error something like "cannot read this of undefined" or something
Modify your player.js as following:
import React from "react";
import { Button } from "evergreen-ui";
export default class player extends React.Component {
constructor(...args) {
super(...args);
this.state = {
shoot: 0
};
}
shoot = ()=>{
this.setState({
shoot: Math.floor(Math.random() * Math.floor(3)),
});
}
render() {
return (
<div>
<h1>hello there</h1>
<h1>{this.state.shoot}</h1>
<Button onClick={() => this.shoot()}>Shoot another
value</Button>
</div>
);
}
}
You have two main issues:
1) You export as default and then your import is wrong.
If you export as:
export default class player extemds React.Component
Then you need to import as:
import player from "./player";
2) Components must start uppercase, otherwise React thinks that they are simple HTML tags and not components.
So you must change player to Player everywhere
I am trying to incorporate mobx with react. Since I spawned my application using create-react-app, I can't use decorators given by mobx.
Given that we can use mobx without decorators as per this documentation: https://mobxjs.github.io/mobx/best/decorators.html
Here's a component that I created:
import React, { Component } from 'react';
import observer from 'mobx-react';
export const TestComponent = observer(class TestComponent extends Component {
render() {
return <div>Just a test component!</div>
}
});
Here's a simple calling of the above component:
import React, { Component } from 'react';
import './App.css';
import Auth from './Auth'
import { TestComponent } from './Test'
import MuiThemeProvider from 'material-ui/styles/MuiThemeProvider';
import AppBar from 'material-ui/AppBar';
import authStore from './stores/Store'
class App extends Component {
constructor(props) {
super(props);
this.state = {
}
}
render() {
return (
<div className="app">
<MuiThemeProvider>
<div>
<TestComponent store={authStore} />
</div>
</MuiThemeProvider>
</div>
);
}
}
export default App;
Now when I run the above component, I get error: Uncaught TypeError: (0 , _mobxReact2.default) is not a function(…) nothing get displays in console.
What am I doing wrong here?
Please use import {observer} from 'mobx-react';
N.B. note that decorators can be used with create-react-app by using custom-react-scripts, as explained here)