When I route my app to another component by using react-router-dom, the CSS doesn't change.
This is a minimalistic version of the code to demonstrate
App.js
import React from 'react';
import Home from './Home';
function App() {
return (
<div>
<Home></Home>
</div>
);
}
export default App;
Home.js
import React from 'react';
import './Home.css';
const Home = () => {
return (
<h1>Home</h1>
);
}
export default Home;
Home.css
body {
background-color: blue;
}
Dashboard.js
import React from 'react';
import './Dashboard.css';
import React from 'react';
import './Dashboard.css';
const Dashboard = () => {
return (
<div className='content'>
<h1>Dashboard</h1>
</div>
);
}
export default Dashboard;
Dashboard.css
.content {
display: flex;
align-content: center;
align-items: center;
}
index.js
import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App';
import Dashboard from './Dashboard';
import * as serviceWorker from './serviceWorker';
import { BrowserRouter as Router, Route } from 'react-router-dom';
ReactDOM.render(
<Router>
<div>
<Route exact path='/' component={App} />
<Route path='/dashboard' component={Dashboard} />
</div>
</Router>, document.getElementById('root'));
// If you want your app to work offline and load faster, you can change
// unregister() to register() below. Note this comes with some pitfalls.
// Learn more about service workers: ...
serviceWorker.unregister();
When I do /dashboard, it loads the Dashboard component, but it keeps the previous CSS that was loaded from the Home component that resides the App component. The background stays blue. I want that when I route to another component because I changed the URL, it loads whatever CSS that new component has attached to it and gets rid of whatever CSS was before. Is that possible?
Edit: I have made an example in CodeSandbox to illustrate. It's a little different from the code above due to the limitations of the playground, but the functionality is the same.
From what can be seen, importing as a module ends up importing it globally. If we comment the line import Home from "./Home"; the blue background disappears. Just importing the component, imports the whole CSS despite the CSS being imported in a modular way. I'm not sure if I am missing something.
Edit 2:
Here are the different solutions I tried:
CSS Modules, but the body style was still globally loaded.
Styled components don't let me modify the body or html selectors CSS. They require me to create a <div> element and
then have that element span the whole body which I would style
as if it was the body. Which is a workaround I don't want to use because for that I rather use CSS Modules for the whole body spanning .
Inline styling also doesn't let me modify the body or html selectors CSS. I would also need to use a workaround like a body spanning <div> as in Styled components.
The problem
When you import a css like you're doing here
import './Home.css';
you're importing it in a global scope, which means it will not disappear once imported.
The solutions
CSS Modules
What you want is either CSS Modules, which is used like this:
import styles from './Home.css';
<a className={styles.myStyleClass}>Hello</a>
Styled components
or a CSS-in-js framework such as styled components which is used like this:
import styled from 'styled-components';
const MyStyledElement = styled.a`
color: blue;
`;
<MyStyledElement>Hello</MyStyledElement>
Regular objects / inline styling
or just "regular" CSS-in-js like:
const myStyle = {
color: blue;
}
<a style={myStyle}>Hello</a>
There are plenty of options when it comes to styling, these alternatives are popular ones that I encourage you to explore and see which you enjoy.
After doing some more tests I have concluded that as of now it is not possible to change whatever CSS styles have been applied to a <body> or <html> selector in an React SPA when a CSS file is already loaded and one uses React Router to render other components. I still appreciate the answers and the time taken to help me find a solution. They are still valid answers if we are not talking about the <body> or <html> node in an HTML document. From them I learned about other ways to use CSS in React. I modified the original post with the solutions I tried.
What ended working was modifying the DOM styles with JavaScript whithin the component itself.
Home.js
import React from "react";
const Home = () => {
// Modify the DOM Styles with JavaScript
document.body.style.backgroundColor = "blue";
// Or uncomment below to modify the
// document root background color
// which in this case would be <html>
//document.bgColor = "blue";
// Or modify the root tag style of the document instead of the
// <body> (<html> in this case)
//document.documentElement.setAttribute('style', 'background-color: green');
return (
<div>
<h1>Home</h1>
<form action="/dashboard">
<input type="submit" value="Go to Dashboard" />
</form>
</div>
);
};
export default Home;
Here is a working example:
Where my app wasn't loading style sheets and the like. However, I was importing my assets directly into my index.html entry point.
By replacing the links with absolute paths as per this documentation, my problem was resolved.
For me, this meant changing
<head>
<link rel="stylesheet" href="./style.css" ></link>
</head>
to this:
<head>
<link rel="stylesheet" href="/style.css" ></link>
</head>
I'm not sure if the same thing would work for your import statements, but it is worth a shot.
More info: styles-not-working-with-react-router
I am trying to overwrite the CSS of react range slider.It uses the custom style sheet of which i need to add in the head section.My project is built on next.js
<link rel="stylesheet" href="https://unpkg.com/react-rangeslider/umd/rangeslider.min.css" />
Otherwise, the slider doesn't show anything if i don't add the link in head even though I installed the library. It's not even overwriting the CSS. I want to change the background color.This is my code:
import React, { Component } from 'react'
import 'react-rangeslider/lib/index.css';
import './slider.css';
import Slider from 'react-rangeslider'
class Horizontal extends Component {
constructor (props, context) {
super(props, context)
this.state = {
value: 850
}
}
handleChangeStart = () => {
console.log('Change event started')
};
handleChange = value => {
this.setState({
value: value
})
};
handleChangeComplete = () => {
console.log('Change event completed')
};
render () {
const { value } = this.state
return (
<div>
<div className='slider' style={{ marginTop:'165px',marginLeft:'319px',width:'700px',backgroundColor:'EF5350'}} >
<div style={{ textAlign:'center',color:'gray',fontSize:'35px',marginBottom:'82px'}}>
<p> What is the size of your property?</p>
</div>
<Slider
min={850}
max={5000}
value={value}
onChangeStart={this.handleChangeStart}
onChange={this.handleChange}
onChangeComplete={this.handleChangeComplete}
/>
<div className='value'>{value}</div>
</div>
</div>
)
}
}
export default Horizontal
I tried to change the background color in slider.css.
.rangeslider-horizontal .rangeslider__fill {
background-color: red;
}
The library needs to be installed first:
npm install react-rangeslider --save
It doesn't work as the slider stylesheet overwrite yours. Include the style like
// To include the default styles
import 'react-rangeslider/lib/index.css'
// import your css
import './style.css';
Demo
always make your own CSS stylesheet file the last file to import after any other CSS stylesheet files to make overwrite you need
otherwise, you can always use the console in the browser to auto-detect any error by pressing F12 in the browser then go to the tab called (console)
I think you can style element you want to live in the console to know the detail of how to nesting element
you also can open the CSS file in the editor and press Ctrl+F then find the line of code you want to style then copy its property and value to your own CSS file and then you can edit it so easy
I want to implement an option to switch between two themes in my React and Redux web app.
I have 2 different CSS files, one for each theme. Right now in order to apply a CSS file's stylings, I simply import it at the head of my App.js.
import '../styles/theme1.css';
const App = (props) => {
return (
<div>
<Header />
<Container/>
</div>
);
};
const mapStateToProps = (state) => ({
theme: state.settings.theme // can return 'theme1' / 'theme2'
});
export default withRouter(connect(mapStateToProps)(App));
So I want to import stylings according to the app's state ('theme1' or 'theme2').
I could think of some messy ways and found some ready-made packages for that, but I want to know if there is a conventional way to do so, efficiently and as clean as possible.
this is a create-react-app kit.
Thank you.
One possibility depending on how your taskrunner configuration is set up would be to introduce React-Helmet, which would allow you to change the CSS reference in your <head> depending on the theme.
import React from "react";
import {Helmet} from "react-helmet";
function StyleSwitch (props) {
return (
<Helmet>
<link rel="stylesheet" href={props.stylesheet} />
</Helmet>
);
};
Try using scss/sass - I think it could simplify the whole process, because it allows you to nest classes/elements.
For example, lets assume you switch between two states, theme1 and theme2:
<div className={this.state.theme}>
<h2>Some text</h2>
</div>
And your .scss file should look like
.theme1{
background-color: black;
h2 {
color: white;
}
}
.theme2{
background-color: white;
h2{
color: black;
}
}
I have default css file and separate css file that should be applied (to owerride default) only when certain conditions are met.
I am using create-react-app wit default import 'file.css' syntax.
What is the best way forward to decide whether to load or not load particular css file dynamically?
The require method only worked in development (as all the CSS is bundled upon build), and the import method did not work at all (using CRA version 3.3).
In our case, we have multiple themes, which cannot be bundled - so we solved this using React.lazy and React.Suspense.
We have the ThemeSelector, which loads the correct css conditionally.
import React from 'react';
/**
* The theme components only imports it's theme CSS-file. These components are lazy
* loaded, to enable "code splitting" (in order to avoid the themes being bundled together)
*/
const Theme1 = React.lazy(() => import('./Theme1'));
const Theme2 = React.lazy(() => import('./Theme2'));
const ThemeSelector: React.FC = ({ children }) => (
<>
{/* Conditionally render theme, based on the current client context */}
<React.Suspense fallback={() => null}>
{shouldRenderTheme1 && <Theme1 />}
{shouldRenderTheme2 && <Theme2 />}
</React.Suspense>
{/* Render children immediately! */}
{children}
</>
);
export default ThemeSelector;
The Theme component's only job, is to import the correct css file:
import * as React from 'react';
// 👇 Only important line - as this component should be lazy-loaded,
// to enable code - splitting for this CSS.
import 'theme1.css';
const Theme1: React.FC = () => <></>;
export default Theme1;
The ThemeSelector should wrap the App component, in the src/index.tsx:
import React from 'react';
import ReactDOM from 'react-dom';
import ThemeSelector from 'themes/ThemeSelector';
ReactDOM.render(
<ThemeSelector>
<App />
</ThemeSelector>,
document.getElementById('root')
);
As I understand, this forces each Theme to be split into separate bundles (effectively also splitting CSS).
As mentioned in the comments, this solution does not present an easy way of switching themes runtime. This solution focuses on splitting themes into separate bundles.
If you already got themes split into separate CSS files, and you want to swap themes runtime, you might want to look at a solution using ReactHelmet (illustrated by #Alexander Ladonin's answer below)
You can use require('file.css') syntax instead. This will allow you to put it inside of a conditional.
e.g.
if(someCondition) {
require('file.css');
}
Use React Helmet. It adds links, meta tags etc into document header dynamically.
Add it into any render method.
import {Component} from 'react';
import ReactHelmet from 'react-helmet';
class Example extends Component{
render(
<ReactHelmet link={
[{"rel": "stylesheet", type:"text/css", "href": "/style.css"}]
}/>);
}
}
You can rewrite it on next <ReactHelmet/> rendering.
One simple solution that I found that works in production is to use vercel's styled-jsx. First, install styled-jsx:
npm install --save styled-jsx
Or if you use Yarn:
yarn add styled-jsx
Now create strings from your css file, so for instance:
const style1 = `
div {
display: flex;
flex-direction: column;
align-items: center;
}
`
const style2 = `
div {
display: flex;
flex-direction: column;
align-items: center;
}
`
And then in your React Component, you can do something like this:
const MyComponent = () => {
return (
<div className='my-component'>
<style jsx>
{
conditionA ? style1: style2
}
</style>
</div>
)
}
Simply add <style jsx>{your_css_string}</style> to the component which you wish to add styling to and you can then to implement conditions just use different strings to import different css styling.
If you are here you most likely are trying to condition a CSS or SCSS import, probably to make some light/dark mode theme or something. The accepted answer works just on mount, after the second css is loaded they are both loaded and you dont have a way to unload them, or actually you have, keep reading...
The use of React lazy and suspense is awesome but in this case we need to help our selves from webpack, because is actually the guy that bundles stuff and can also unbundle stuff, which is what you need, a toggle of css imports basically
Adding webpack lazyStyleTag
Go to your webpack config file and add the following rules
module.exports = {
module: {
rules: [
{
test: /\.css$/i,
// Probly you already have this rule, add this line
exclude: /\.lazy\.css$/i,
use: ["style-loader", "css-loader"],
},
// And add this rule
{
test: /\.lazy\.css$/i,
use: [
{ loader: "style-loader", options: { injectType: "lazyStyleTag" } },
"css-loader",
],
},
],
},
};
Now take your CSS files and change their name to the lazy named convention
You probably have this
styles.css
// or
styles.min.css
Now will be this:
styles.lazy.css
Then create your React theme Provider in a simple React context, this context will wrap your App so it will load the conditioned CSS everytime the context state changes. This context state is going to be availabe anywhere inside your app as well as the setter via a custom hook we will export from the same file, check this out:
import React, {
useEffect, createContext, useState, useContext,
} from 'react';
import { Nullable } from 'types';
// Import both files here like this:
// Import of CSS file number 1
import LightMode from './theme/styles.lazy.css';
// Import of CSS file number 2
import DarkMode from './theme/styles.lazy.css';
interface IContext {
theme: Nullable<string>
toggleTheme: () => void
}
const Context = createContext<IContext>({
theme: null,
toggleTheme: () => { },
});
// Your Provider component that returns the Context.Provider
// Let's also play with the sessionStorage, so this state doesn't
// brake with browser refresh or logouts
const ThemeProvider: React.FC = ({ children }) => {
// Im initialazing here the state with any existing value in the
//sessionStorage, or not...
const [theme, setTheme] = useState<Nullable<string>>(sessionStorage.getItem('themeMode') || 'dark');
// this setter Fn we can pass down to anywhere
const toggleTheme = () => {
const newThemeValue = theme === 'dark' ? 'light' : 'dark';
setTheme(newThemeValue);
sessionStorage.setItem('themeMode', newThemeValue);
};
// Now the magic, this lazy css files you can use or unuse
// This is exactly what you need, import the CSS but also unimport
// the one you had imported before. An actual toggle of import in a
// dynamic way.. brought to you by webpack
useEffect(() => {
if (theme === 'light') {
DarkMode.unuse();
LightMode.use();
} else if (theme == 'dark') {
LightMode.unuse();
DarkMode.use();
}
}, [theme]);
return (
<Context.Provider value={{ theme, toggleTheme }}>
{children}
</Context.Provider>
);
};
export default ThemeProvider;
// This useTheme hook will give you the context anywhere to set the state of // theme and this will toggle the styles imported
export const useTheme = () => useContext(Context);
Remember to put this state on the sessionStorage like in this example so your user has the state available every time it comes back or refreshes the page
Don't forget to wrap the friking App with the Provider:
import ThemeProvider from './ThemeProvider'
const App = () => {
return (
<ThemeProvider>
<App />
</ThemeProvider>
)
}
Now just toggle the CSS imports of your application using your cool useTheme hook
import { useTheme } from './yourContextFile';
// inside your component
const AnyComponentDownTheTree = () => {
const { theme, toggleTheme } = useTheme()
// use the toggleTheme function to toggle and the theme actual value
// for your components, you might need disable something or set active a
// switch, etc, etc
}
Other solution does not work for me. After one day of the search, I obtain bellow solution. In my issue, I have two CSS files for RTL or LTR like app.rtl.css or app.ltr.css
Create a functional component Style like this:
import React, { useState } from "react";
export default function Style(props) {
const [stylePath, setStylePath] = useState(props.path);
return (
<div>
<link rel="stylesheet" type="text/css" href={stylePath} />
</div>
);
}
And then you can call it, for example in App.js:
function App() {
...
return (
<Style path={`/css/app.${direction}.css`} />
)}
direction param contains rtl or ltr and determine which file should be loaded.
I tested some alternatives available in some tutorials and the best for me was to use only classes in css.
One of the problems I encountered when using
require: did not override on some occasions
import: delay generated to load css
The best way for me was to actually put a class switch
.default-sidebar {
--side-text-icon:rgba(255,255,255,.9) !important;
--side-text-section: rgb(255,255,255,.8) !important;
--side-separator-section:#ff944d !important;
}
.dark-sidebar {
--side-text-icon:rgba(255,255,255,.9) !important;
--side-text-section: rgb(255,255,255,.8) !important;
--side-separator-section:#262626 !important;
}
'
<div className={`root-sidebar ${condition?'default-sidebar':'dark-sidebar'}`}></div>
Greetings fellow meteorites!
I am in the process of including material ui (react based) into an existing blaze app. I'm using the meteor guide and the material-ui docs as my instructions to do this properly but unfortunately to no avail. Has anyone successfully done this before? According to the material-ui docs you are supposed to inject an MuiThemeProvider into your main App Component but I keep getting the following error:
MuiThemeProvider.render(): A valid React element (or null) must be returned. You may have returned undefined, an array or some other invalid object.
Here is my root blaze html template:
<template name="main">
<head>...</head>
<body>
<div id="wrap">
<div id="react-app-wrapper">
{{> React component=App}}
</div>
</div>
</body>
</template>
Notice I am using https://guide.meteor.com/react.html#react-in-blaze as my guidelines and am using the meteor package react-template-helper.
Here is my main.js file:
if(Meteor.isClient){
import App from './users/client/ui/components/App.js';
Template.main.onCreated(function(){
});
Template.main.helpers({
'App' : function(){
return App;
}
}
And my App.js Component File:
import React, { Component, PropTypes } from 'react';
import lightBaseTheme from 'material-ui/styles/baseThemes/lightBaseTheme';
import getMuiTheme from 'material-ui/styles/getMuiTheme';
import MuiThemeProvider from 'material-ui/styles/MuiThemeProvider';
const lightMuiTheme = getMuiTheme(lightBaseTheme);
export default class App extends Component{
constructor(props){
super(props);
}
render() {
return (
<div>
<MuiThemeProvider muiTheme={lightMuiTheme} >
</MuiThemeProvider >
</div>
);
}
}
Appreciate your help big time! I have tried everything and feeling pretty stumped right now. :( If you give the correct answer I will obviously mark it as so!
Alex
This is how MuiThemeProvider renders
render() {
return this.props.children;
}
And therefore it, React actually, complained of nothing to render since this is you use it.
render() {
return (
<div>
<MuiThemeProvider muiTheme={lightMuiTheme} >
{/* There should be something here. */}
</MuiThemeProvider >
</div>
);
}
Start to put some contents that it can serve for you.
A side notice here is that the outer <div> wrapper can be dropped on the premise that it is not of some particular use.
Good luck!