React functional component won't display - reactjs

I've started to learn React lately and today to just memorize what i've learnt i decided to create a react component that contains a simple heading tag but i can't figure out why it won't be displayed in the browser here's my code
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<div id="app">
</div>
<script crossorigin src="https://unpkg.com/react#18/umd/react.development.js"></script>
<script crossorigin src="https://unpkg.com/react-dom#18/umd/react-dom.development.js"></script>
<script src="include-component.js" ></script>
</body>
</html>
and this is my react component which resides in file named include-component.js :
import React from "react";
import ReactDOM from "react-dom";
function IncludeComponent() {
return(
<TestComponent name="Hello Wolrd"/>
);
}
function TestComponent(props) {
return(
<h1>{props.name}</h1>
);
}
const app= document.getElementById('app');
ReactDOM.render(<IncludeComponent/>,app);
can someone tell me why my component won't render ?

You are using a confusing mixture of non-compiled code and compiled code. Did you checked your console? You surely have errors guiding you...
This is for when you don't have a compiler and React and ReactDOM will be available globally:
<script crossorigin src="https://unpkg.com/react#18/umd/react.development.js"></script>
<script crossorigin src="https://unpkg.com/react-dom#18/umd/react-dom.development.js"></script>
I don't recommend you try this approach. It is sub optimal and none of the resources you will see online are using it.
Then you do this:
<script src="include-component.js"></script>
This will already cause an exception since you're using import statements inside this JS file, but you haven't said that it type="module". Normal JS files can't use import statements.
Finally you can't import React and ReactDOM like that anyway, since you imported the browser versions which just have global variables.
Instead just start a project with Create React App:
npx create-react-app my-app
cd my-app
yarn start
And start experimenting in that instead.
For completeness you would need to transform with babel:
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<div id="app">
</div>
<script src="https://unpkg.com/react/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom/umd/react-dom.development.js"></script>
<script src="https://unpkg.com/#babel/standalone/babel.js"></script>
<script type="text/babel">
function IncludeComponent() {
return(
<TestComponent name="Hello Wolrd"/>
);
}
function TestComponent(props) {
return(
<h1>{props.name}</h1>
);
}
const container = document.getElementById('app');
const root = ReactDOM.createRoot(app);
root.render(<IncludeComponent/>);
</script>
</body>
</html>

You must import the test component!!
import TestComponent from './TestComponent';
function App() {
return (
<div className="App">
<TestComponent name='hello world' />
</div>
);
}
export default App;

Related

Visual Studio Code with React

I am trying to use React with MS Visual Studio Code. If I ran the program from the terminal, I get following error message: "Cannot use import statement outside a module"
If I run the program without terminal, it takes me to the browser (Firefox) and gives "File not found" error message.
Not sure how the above two are connected. Is this is a problem with node installation, location of my files (where I do the actual programming), or perhaps is has something to do with Firefox debugger.
Kindly ask for help.
Many thanks.
Here is the code:
import React from "react";
import { ReactDOM } from "react-dom";
class App extends React.Component {
render() {
return (
<div>Test div</div>
);
}
}
ReactDOM.render(<App />, document.getElementById("App"));
I am also providing a code to my .html, in case it is relevant:
<!DOCTYPE html>
<html lang="eng">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Calculator</title>
<link rel="stylesheet" href="/src/Dejan/Kalkulator/calc.css">
</head>
<body>
<h1 id="test">Testing the system</h1>
<script src="/src/Dejan/Kalkulator/calc.js"></script>
</body>
<div id="App"></div>
</html>
Hey Deyan doesn't add into the HTML file, because react will automatically handle that, and also don't use CSS in HTML it will cause weird behavior at the end.
And don't put App div outside of the body tag. Because inside that div your whole react app will be fitted.
import React from "react";
import { ReactDOM } from "react-dom";
import "./Dejan/Kalkulator/calc.css"; // and add css like this I don't know your file path use the correct I put randomly.
class App extends React.Component {
render() {
return (
<div>Test div</div>
);
}
}
ReactDOM.render(<App />, document.getElementById("App"));
<!DOCTYPE html>
<html lang="eng">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Calculator</title>
</head>
<body>
<div id="App"></div>
</body>

Reactjs code is not rendering HTML component properly

I am new to React and would like to ask why the following code in vs code wont render the h1 component in my html page?
When I run the html page, it just shows empty page. Anyone know what is happening?
Code as follows:
My index.html code as follows:
<!DOCTYPE html>
<html lang="en">
<head>
<script crossorigin src="https://unpkg.com/react#17/umd/react.development.js"></script>
<script crossorigin src="https://unpkg.com/react-dom#17/umd/react-dom.development.js"></script>
<script src="https://unpkg.com/babel-standalone#6/babel.min.js"></script>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>React</title>
</head>
<body>
<div id="root"></div>
<script src="index.js" type="text/babel"></script>
</body>
</html>
My index.js code as follows:
ReactDOM.render(<p>Hello, everyone!</p>,document.getElementById("root"))
Whenever I run the html file, it just shows blank page rather than "Hello, everyone!". Does anyone know what is going on here?
index.js
import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App';
ReactDOM.render(
<React.StrictMode>
<App />
</React.StrictMode>,
document.getElementById('root')
);
React uses JSX to render all the components. This means in simple terms, it collects all the components and converts them into an HTML page.
React renders each component as a tree. So it is not advisable to add all your code to a single component. As in your case, you tried to print Hello Everyone! on the render function without specifying the HTML tag.
App.js
import React from "react";
function App() {
return (
<div>
<h1>Hello Everyone</h1>
</div>
);
}
export default App;
If you're wondering how I'm importing App.js and CSS files, It is called path specifying for the files. If the files are present are on the same folder then use ./filename.extension(css/js)
What is React.StrictMode?
It renders all the child components in strict mode.
This prevents certain actions being taken and throws errors/warnings if there are any
Most importantly it does a lot of checking which will be really helpful to correct all the possible errors.
You should not open the HTML page to see changes instead use any package managers to run the react code. For Example:
npm start or yarn start
All the best! 😁
<html>
<head>
<script
src="https://unpkg.com/react#17/umd/react.development.js"
crossorigin
></script>
<script
src="https://unpkg.com/react-dom#17/umd/react-dom.development.js"
crossorigin
></script>
<script src="https://unpkg.com/#babel/standalone/babel.min.js"></script>
</head>
<body>
<div id="root"></div>
<script type="text/babel">
ReactDOM.render(<p>Hello world!</p>, document.getElementById("root"));
</script>
</body>
</html>
here you have to specify the data-preset="react"
<script src="index.js" type="text/babel" data-preset="react"></script>
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<script crossorigin src="https://unpkg.com/react#17/umd/react.development.js"></script>
<script crossorigin src="https://unpkg.com/react-dom#17/umd/react-dom.development.js"></script>
<script src="https://unpkg.com/babel-standalone#6/babel.min.js"></script>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>React</title>
</head>
<body>
<div id="root"></div>
<script src="index.js" type="text/babel" data-preset="react"></script>
</body>
</html>

My hello world React not appear

I am new to React. I read the official tutorial of React and I try to create a basic hello world react app but I dont succeed.
I looked in the web and also here for an answer and I didnt find one.
Can you please tell me what I am missing and what I need to do?
The following is my html and javascript files:
import React from 'react';
import ReactDOM from 'react-dom';
ReactDOM.render(
<h1>Hello, World</h1>,
document.getElementById('root')
);
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<title>Page Title</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css">
<script src="https://unpkg.com/react#16/umd/react.development.js" crossorigin></script>
<script src="https://unpkg.com/react-dom#16/umd/react-dom.development.js" crossorigin></script>
<script type="text/jsx" src="inputPhoneNumber.js"></script>
</head>
<body>
<div class="jumbotron jumbotron-fluid">
<div id="root" class="container">
</div>
</div>
</body>
</html>
All you should need is the react and react-dom scripts like you already have, a root element like the div with id root you have, and a file which uses ReactDOM to render the topmost component into the root element.
Example
ReactDOM.render(
React.createElement('h1', {}, 'Hello, World'),
document.getElementById('root')
);
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<div id="root"></div>

How do I import pre built in components from a cdn js?

I am trying to use some pre-builtin react component from a library called ant design. Also, I would like to call the react and the component library through a cdnjs(don't wish to use webpack or else). How could I accomplish it? My approaches are like below and it's not working for me.
<!DOCTYPE html>
<html>
<head>
<title></title>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/antd/3.1.6/antd.min.css" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.4.2/react.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.4.2/react-dom.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/babel-standalone/6.21.1/babel.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/antd/3.1.6/antd.min.js"></script>
</head>
<body>
<div id="root"></div>
<script type="text/babel">
import Button from 'antd/lib/button';
class Greeting extends React.Component {
render() {
return (<p><Button type="primary">Primary</Button></p>);
}
}
ReactDOM.render(
<Greeting />,
document.getElementById('root')
)
</script>
</body>
</html>
You don't need to import, because when you use prebuilt version, it's already injected into a global variable call 'antd' (just like React)
I also updated a little bit your scripts because for React you need . the umd version and antd needs the with locale version.
However, using prebuilt version is strongly NOT RECOMMENDED be careful.
<!DOCTYPE html>
<html>
<head>
<title></title>
<link rel="stylesheet" href="https://unpkg.com/antd/dist/antd.css" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.2.0/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.2.0/umd/react-dom.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/babel-standalone/6.21.1/babel.min.js"></script>
<script src="https://unpkg.com/moment/min/moment-with-locales.js"></script>
<script src="https://unpkg.com/antd/dist/antd-with-locales.js"></script>
</head>
<body>
<div id="root"></div>
<script type="text/babel">
const { Button } = antd;
class Greeting extends React.Component {
render() {
return (<p><Button type="primary">Primary</Button></p>);
}
}
ReactDOM.render(
<Greeting />,
document.getElementById('root')
)
</script>
</body>
</html>

ReactJS Simple Component Not Shown

I'm trying to render a small search bar onto my website, but what I see is that it is still existing in the website, but its size becomes 0x0, and I can't find anything wrong with my ES6 code. Can someone debug for me please?
index.html:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="/style/style.css">
<!-- <script src="https://maps.googleapis.com/maps/api/js"></script> -->
<!-- Latest compiled and minified CSS -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" integrity="sha384-1q8mTJOASx8j1Au+a5WDVnPi2lkFfwwEAa8hDDdjZlpLegxhjVME1fgjWPGmkzs7" crossorigin="anonymous">
<!-- Optional theme -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap-theme.min.css" integrity="sha384-fLW2N01lMqjakBkx3l/M9EahuwpSfeNvV63J5ezn3uZzapT0u7EYsXMjQV+0En5r" crossorigin="anonymous">
<title>React-Redux-Learning</title>
</head>
<body>
<div id="container"></div>
<!-- jQuery (necessary for Bootstrap's JavaScript plugins) -->
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
<!-- Latest compiled and minified Bootstrap JavaScript -->
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js" integrity="sha384-0mSbJDEHialfmuBBQP6A4Qrprq5OVfW37PRR3j5ELqxss1yVqOtnepnHVP9aJ7xS" crossorigin="anonymous"></script>
</body>
<script src="/bundle.js"></script>
</html>
index.js:
import React from 'react'
import ReactDOM from 'react-dom'
import searchBar from './components/searchBar'
const youtubeAPIKey = '...'
const App = () => {
return (
<div>
<searchBar />
</div>
)
}
ReactDOM.render(<App />, document.getElementById('container'))
searchBar.js:
import React, { Component } from 'react'
class searchBar extends Component {
constructor(props) {
super(props)
this.state = {term: ''}
}
render() {
return <input onChange={event => console.log(event.target.value)}/>
}
}
export default searchBar
First of, you have defined your component as <searchBar\>. I guess React is not able to see it as JSX Component and is embedding it as a plain html tag instead, as evidenced by the <searchbar\> tag seen in Elements tab of chrome.
I think what you need is, to figure out why react is not able see searchBar as a JSX component. I hope this leads you to the right direction.
OK my boss actually found it out, it's the problem about CAPITALIZING the variable names. After I cap the first letter of the variable names things are working again...
Your search bar code works fine. Check your CSS to make sure that your body has a size.

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