Use SASS subclasses in React - css

My SCSS code :
.motherClass {
...
.subClass {
...
}
}
My TSX code :
return <div className={styles.motherClass}>
<div className={ ??? }>
...
</div>
</div>
In order to apply the subClass class to the child HTML element, how one would proceed ?
I have tried with
className="subClass"
className={styles.motherClass.subClass}
But none seems to work. Is there a way to do it ?
(It seems obvious, but I would like not to escape the sub class from the mother class for encapsulation reasons, so this solution is not on the table)

className={styles.subClass}
When using CSS modules, each class created in CSS/SCSS file is available as a property on the exported object.
Nesting has no effect on that, it only affects resulting selectors.

Related

inline style vs className in Componet context

Hello I try to understand when it's necessary to use inline style instead className in this case. I take a long time to solve my problem of translation. At the beginning I want to translate component by using classNameand that's don't work. it's very weird because in my point of view there is no reason that's happen. So I figure there is something wrong in my code, but what... I have not yet found. So I finish trying to translate by using a inline style. Miracle, that's work fine.
My question is why ?
Work well
export function Content() {
return (
<div style={{transform: 'translateY(100px)'}}>
<Test/>
<Footer />
</div>)
}
don't work
export function Content() {
return (
<div className={container_content}>
<Test/>
<Footer />
</div>
)
}
css
.container_content {
transform: translateY(100px);
}
Nota bene :
The problem is not from the method. To use className in my jsx
must be like that:
import { container_content } from "./test.module.css";
and next
<div className={container_content}><div>
So this part of code is good, the issue seems to come from elsewhere...
What's happening is that when you use the inline style you are passing an object that includes the styling for that component. When you use the className you need to pass in a string for the class you want to use. Right now you are passing a variable name. Either of these works:
<div className={"container_content"}>
OR
<div className="container_content">
If you think about it in regular html you would do
<div class="container_content">
EDIT: Given your updated question, you should just import the css file with:
import "./test.module.css"
and then use the solution I mentioned.
inside the js file, you need to import the CSS file like this
import " css-file-dir";
and then you can Reference to the CSS classes inside your component as a string
example :
className="container_content"

How to load different .css files on different components of a react application?

I have two .jsx files that represent their respective components.
The first one is, Blog.jsx
import React from "react";
import '../assets/css/blog.css';
export const Blog = () => (
<div>
<h1>Hello Blog</h1>
</div>
)
With its respective CSS file, blog.css
div { background: #ff481f; }
and the second one is, Landing.jsx
import React from "react";
import '../assets/css/landing.css'
export const Landing = () => (
<div>
<h1>Hello Landing</h1>
</div>
)
With its respective CSS file, landing.css
div { background: #86ff2b; }
I have added routing and called instances of those two components on the App.js file which is the default file of a React application. After running the application, when navigated to components, I faced a problem that the background color is the same for both of the components (It loads landing.css only and never changes).
How can I fix that problem that each component only uses its respective .css file and loads it?
By default webpack and other build tools will compile all CSS files into one, even if css was imported in separate JSX files. So you can't use different CSS files and expect you don't affect on another part of page.
You have some options:
Use BEM for naming class names.
Use cssModules. In this case elements will have their own css class name and styles will not affect any other elements except if you use :global selector.
css-module
Using html tags as css selectors is a bad practice (because there is the behaviour you describe).
You should use only css classes or inline styles (using id's is another bad practise, id's have high priority).
div {
width: 20px;
height: 20px;
}
#id {
background: red;
}
.class {
background: green;
}
<div id="id" class="class"></div>
In case using css classes there is the same problem (when you have two similar classes). And this case is decided using css modules (set of rules of building) or you can use css-in-js (external library) which has its pros and cons. Also you can use BEM (methodology) and if your application is not big you can avoid this trouble.
css modules will add to your classes random hash and instead .my-awesome-class-name you will get .my-awesome-class-name-dew3sadf32s.
So, if you have two classes .class in the first file and .class in the second file in the end you will get two classes .class-dew23s2 and .class-dg22sf and you styles will resolve as expected.
css-in-js is a similar way except you should write your styles using javascript with some profits like including only those styles that are needed at the moment (what you are looking for right now) and several others.
You can code using pure css / scss / postcss / etc but many companies already choose between css modules and css-in-js.
BEM is just naming conventions for your class names.
And lastly - if you use inline-styles using react you should remember:
{} is constructor of object and {} returns new object on every call, it's mean if you write something like:
class MyAwesomeComponent extends Component {
render() {
return <div style={{color: "red"}}></div>;
}
}
or
class MyAwesomeComponent extends Component {
render() {
const divStyles = {color: "red"};
return <div style={divStyles}></div>;
}
}
div will re-render every time your render will call because div takes new prop.
Instead, you should define your styles (for example) in outside of your class:
const divStyles = {color: "red"};
class MyAwesomeComponent extends Component {
render() {
return <div style={divStyles}></div>;
}
}
Don't define your css using HTML tags because it will affect your entire application.
use className,id or inline styling.
like- App.css
.myApp{ color: red;}
#myApp2{ color: blue;}
App.js
import './App.css'
<div className="myApp">color changed by className</div>
<div id="myApp2">color changed by id</div>
<div style={{color:'red'}}>color changed by inline object styling</div> // inline styling
This is not the best solution if you are looking forward to improve yours css imports/loads.
However could be the best solution if you dont want to go in deep in css, resolve the problem fast and keep working with HTML tag.
You can add a div for each component, define an Id for the div and wrap the component. Afterwards in the component's css fies you are going to define all the styles starting with the #id so all the css classe or HTML tag will affect just the corresponding component.
//App render in root
ReactDOM.render(
<App />,
document.getElementById('root')
);
//App
function App(props){
return [
<Blog />, <OtherComponent />
]
}
//Blog component
function Blog(props){
return <div id="blog">
<h1>I am Blog</h1>
</div>
}
//Other component
function OtherComponent(props){
return <div id="otherComponent">
<h1>Im am other component</h1>
</div>
}
/* blog.css*/
#blog h1{
color:yellow;
}
/* otherComponent.css*/
#otherComponent h1{
color:green;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<div id="root"></div>

How to dynamically generate CSS class and/or set its property

The title is not really a question it is more like an idea, I don't know what approach is best for my situation.
So, the problem. I have some 3rd party component that have some complex structure and styling. Some part of it has some predefined CSS class that I can override with CSS in my surrounding component. Something like this:
my component:
<div class="my-cmp-container">
<some-3rd-party-cmp></some-3rd-party-cmp>
</div>
3rd party component:
<div class="3rd-party-css-class">
...
</div>
For example, 3rd-party-css-class has style background-color: #f00, I can override it with .my-cmp-container .3rd-party-css-class { background-color: #fff; } etc. But. What if I need to set color dynamically, it's stored in a DB for example and I can't predefine each case in my class' CSS. I just have the color in hex.
In theory I can generate unique string to set as CSS class for every instance of some-3rd-party-cmp and somehow generate CSS in my component? I'm lost a little, what is the best approach for this?
Edit: Code sample to illustrate the situation https://stackblitz.com/edit/angular-kxdatq
What you are trying to do is the subject of this open issue about stylesheet binding in Angular. Until that feature is available, you can get what you want with a custom directive. Here is a directive that retrieves the checkbox element generated by ng-zorro-antd and applies two color attributes to it. The two colors are #Input properties and the directive implements OnChanges which allows to react to property binding changes.
#Directive({
selector: "[nz-checkbox][nz-chk-style]"
})
export class CheckBoxStyleDirective implements OnInit, OnChanges {
#Input("nz-chk-bkgnd") chkBkgndColor: string;
#Input("nz-chk-border") chkBorderColor: string;
private checkbox: HTMLElement;
constructor(private renderer: Renderer2, private el: ElementRef) { }
ngOnInit() {
this.checkbox = this.el.nativeElement.querySelector(".ant-checkbox-inner");
this.updateBackgroundColor();
this.updateBorderColor();
}
ngOnChanges(changes: SimpleChanges) {
if (changes.chkBkgndColor) {
this.updateBackgroundColor();
}
if (changes.chkBorderColor) {
this.updateBorderColor();
}
}
updateBackgroundColor() {
if (this.checkbox) {
this.renderer.setStyle(this.checkbox, "background-color", this.chkBkgndColor);
}
}
updateBorderColor() {
if (this.checkbox) {
this.renderer.setStyle(this.checkbox, "border-color", this.chkBorderColor);
}
}
}
Once the directive attribute selector nz-chk-style is applied to the 3rd party element, you can set the checkbox background and border colors with property binding as follows:
<span nz-checkbox nz-chk-style [nz-chk-bkgnd]="bkgndColor" [nz-chk-border]="borderColor" >
See this interactive stackblitz for a demo.
Not sure if you are using Angular but you tagged it, so I guess you are.
If you want to change only the color and nothing more, instead of having a .3rd-party-css-class class, you could just have your with an ng-style like so:
<some-3rd-party-cmp ng-style="{ color: your_color_hex_variable }"></some-3rd-party-cmp>
You can also define a whole object if styles and pass it.
You can also use ng-class and pass one or an array of class names what you want to put additionally on your component:
<some-3rd-party-cmp ng-class="[cls1, cls2, cls3]"></some-3rd-party-cmp>
<some-3rd-party-cmp ng-class="[3rd-party-css-class, someCondition ? 'another-class-name' : '']"></some-3rd-party-cmp>
In the classes you can define the css rules you want to apply and thats it.
With this solutions you can avoid having extra wrapper elements for styling purposes which is a nice thing.

Styling from separate CSS files not applied with new components

I have been trying to build a small project with React for the past few days and all went great until today. For some reason, no CSS is applied to new components! All the CSS that worked before is still up and running but if I'd add something like a div in between an already existing div, the new div will not pick up any CSS!
Example:
<div className="DivStyle"> // Styling applied!
<div className="DivStyle"> </div> // Styling completely ignored!
<div>
It is probably worth mentioning that I am still able to style the components inline.
Also, looking at the sources in Chrome, the styles are uploaded!
Here is my concrete example:
import '../styles/drawers.css';
class BottomFilterDrawer extends React.Component<IBottomFilterDrawerProps, IBottomFilterDrawerState> {
...
public render() {
return(
<Drawer
open={this.state.isOpen}
anchor="bottom"
// tslint:disable-next-line jsx-no-lambda
onClose={() => this.toggleDrawer(false)}>
<div className="BottomDrawerContainer" style={{margin: "10px"}}> // Styling for "BottomDrawerContainer" class not applied!
...
</div>
</Drawer>
);
}
}
The CSS file:
#BottomDrawerContainer {
margin: 10px;
}
I am certain that the import path is correct, Typescript wouldn't even let me run it if it weren't.
You are applying css for class not for id. So your css must be like below.
.BottomDrawerContainer {
margin: 10px;
}
if you want to apply for inner div.
.DivStyle .DivStyle {
//style for inner div
}
do not use again same id, React create error and if show any error first you solve error otherwise browser not show anything

Change CSS class's property on click

I've read around a little bit and have a good start to what I ultimately want. This was helpful, along with another article which I forgot the link to. However, everything I've read ADDS a CSS class or property to an element. I want to CHANGE a property of an existing CSS class, but I don't know how to target it.
I think I want to use ng-class in one of these use cases taken from the Angular documentation:
If the expression evaluates to a string, the string should be one or more space-delimited class names.
If the expression evaluates to an object, then for each key-value pair of the object with a truthy value the corresponding key is used as a class name.
My existing code uses ng-class along with some controller logic.
HTML
<div ng-controller="ngToggle">
<div ng-class="{'inset-gray-border' : style}">
<div class="subcontainer" ng-click="toggleStyle()">{{item.name}}</div>
</div>
</div>
This currently adds the inset-gray-border class to the nested div, but I just want to change the border property in the subcontainer class.
Controller
angular.module('app').controller('ngToggle', ['$scope', function($scope) {
$scope.style = false;
$scope.toggleStyle = function() {
$scope.style = $scope.style === false ? true: false;
};
}]);
I considered using a directive, but I believe that would be overkill. I think this can be achieved in a controller.
EDIT: After further research I think jQLite can do the trick, but that would probably require a directive.
CHANGE a property of an existing CSS class
Add a css rule that does that using the new class you added using ng-class. The specificity will over ride the original rule
.subcontainer{
color : blue
}
.inset-gray-border .subcontainer{
color:red
}
Instead of a big toggleStyle function, you can write that stuff in UI side only.
Here is fiddle. As you want to change border property of .subcontainer, Overwrite that property by adding .insert-gray-border
<div ng-controller="ngToggle">
<div >
<div ng-class="{'subcontainer':true,'inset-gray-border' : style}" ng-click="style=!style">{{item.name}}</div>
</div>
</div>
The benifit of this is , it uses local scope instead of controller scope.
The best bet would be to have two CSS classes defined, one for the base (untoggled) case, another with all the properties that you want for when the property is toggled on.
In this case you may want something like:
.container .subcontainer {}
.container .subcontainer-bordered { border: solid 1px #123456}
Then your HTML code be updated to reflect this structure
<div ng-controller="ngToggle">
<div class="container">
<div class="subcontainer" ng-class="{'subcontainer-bordered': style}" ng-click="style = !style">{{item.name}}</div>
</div>
</div>

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