In my ReactJS project I have defined a property in my index.css file:
.container {margin: auto}
And in my component.module.css file I have:
.component {margin-top: 6rem}
On my element I add both classes (.container and .component).
It looks like the global property value has higher specificity than the local one. If I add !important to the local value, it overrides but I would prefer not to do so. Is this expected or have I done something wrong?
On the other hand, when I declare properties for elements in my global index.css file:
button {color: red}
and later style the same element locally in component.module.css:
button {color: white}
The local value has higher specificity (the button is white).
So for element styles, local values has higher specificity and for classes it's opposite?
Thank you for the reply and leading me to the solution. It was indeed the order of loading of the CSS files. I forgot to mention that I had already considered this and tried to switch the order of the classes I point to:
const componentClasses = `global-class ${classes['local-class']}`
<Component className={componentClasses}>
to
const componentClasses = `${classes['local-class']} global-class `
However, this didn't change the styles applied.
The change that was needed was the order of which I import the global CSS file vs. the component which needed styling.
So instead of
import Component from './Component ';
import './index.css';
do this:
import './index.css';
import Component from './Component ';
Please forgive me as I'm still new to SO. For a minimum reproducible example, will this link do?
https://codesandbox.io/s/css-global-vs-local-import-order-0urhmm
In the index.js file you can switch the order of the imported App component and the index.css file to see changes in styling. I hope I'm not breaching any of the rules here. Thanks again.
Edit: Link changed.
Related
I am facing an issue which is mind-numbing in the world of CSS.
TailwindCSS 3 classes just doesn't override previous classes.
For example, there is this component, I created:
import * as React from "react";
const TextBox = ({ addClassName, children }) => {
const className = `text-xl leading-7.5 font-lato font-normal ${addClassName}`;
return <div className={className}>{children}</div>;
};
export default TextBox;
Then I go ahead and use this component above at another place, like this:
<TextBox addClassName="text-4xl">My New Text</TextBox>
Now when I inspect it in the browser, it shows both of the font-size:
Screenshot from the browser inspect
class="text-xl leading-7.5 font-lato font-normal text-4xl"
As you can see both of the classes are there, both referring to font-size, and the larger one is after the smaller one.
And still ONLY the small ( the original ) font-size will be the dominant.
( as a side note, I did try to put the addClassName variable in the front as well, no help )
Why is this?
I appreciate any help getting with this.
Thank you
I found the answer from dev.to.
The reasons your code didn't work are:
It turns out that the space-separated CSS class list that the class HTML attribute accepts is not treated as a list when calculating CSS rules precedence by the browser. The class attribute actually contains the set of classes the element has, so the order doesn't matter.
As the order that the classes appear in the class attribute doesn't matter, the rule that comes later in the CSS stylesheets wins.
Moreover, it wasn't warranted that the 'text-4xl' was defined after the 'text-xl' in the CSS stylesheet.
So to solve this problem, I recommended using tailwind-merge to override previous classes.
Tailwind-merge is a utility function to efficiently merge Tailwind CSS classes in JS without style conflicts.
One of its features was: Last conflicting class wins
twMerge('p-5 p-2 p-4') // → 'p-4'
Quoting from redit
In CSS if you have two selectors with equal specificity the one that comes last in the CSS structure takes precedence. The order in the class attribute has no effect.
Suggested solution would be to write your own class after tailwindcss import statement, or edit it using inline style.
My personal tip: Don't use two classes that target the same css property, text-lg and text-4xg both target font-size, you need a way (suggest clsx lib) to put only one class name and not the other
import clsx from 'clsx';
let condition = false;
function Component(){
return (
<div>
<p className={clsx({
"text-lg": condition,
"text-4xl": !condition,
})}>
...
</p>
</div>
);
}
I have had the same problem, and didn't want to add yet another dependency and increase my app's bundle size to solve something that doesn't have to be this hard. So I looked into the tailwind docs and found this:
Use the components layer for any more complicated classes you want to
add to your project that you’d still like to be able to override with
utility classes.
#tailwind base;
#tailwind components;
#tailwind utilities;
#layer components {
.card {
background-color: theme('colors.white');
border-radius: theme('borderRadius.lg');
padding: theme('spacing.6');
box-shadow: theme('boxShadow.xl');
}
/* ... */
}
By defining component classes in the components layer, you can still
use utility classes to override them when necessary:
<!-- Will look like a card, but with square corners -->
<div class="card rounded-none">
<!-- ... -->
</div>
Though this means you will have to write a component class every time you want to override an element with predefined classes.
https://tailwindcss.com/docs/adding-custom-styles#adding-component-classes
I would suggest you to try clsx or clsssnames for better usage with tailwind classes instead of string interpolation
I found a Solution guys.
Setup props with default CSS values at the original component, and then at the time of the usage of this aforementioned component, if we need different style, we just gave that in the props.
I am currently working on my first website in react. In my main.module.css I have
* {
padding: 0;
margin: 0;
box-sizing: border-box;
}
Just typical css styling reset. But React returns the error:
Syntax error: Selector "*" is not pure (pure selectors must contain at least one local class or id)
Do you have any solution for that? I want to keep this styling reset instead of adding those three lines to every element i have.
You should not have styling reset in module.css file.
Move this css reset to normal css file like index.css file.
Styling file with .module.css extensions are used to define the styling you can say local to a components. It means that if you import a module.css file in two different components, both components will have same styles with different class names. This one prevents overriding of styles.
That would go into global styles, which can be done by simply adding:
require('./name-of-your-global-style.css');
I have a Parent.js component with a child component Child.js inside of it.
Parent.js imports parents.css
Child.js imports child.css
If I define this in child.css:
.example {
font-family: 'Roboto', sans-serif;
}
How come I'm able to use this className in the Parent.js component as well despite not specifying it in the parent.css?
Unless you use unique class names, CSS Modules or some other alternatives available for scoping CSS styles to any component in React, styles specified in any CSS file will be applied globally.
If you want to limit styles to any component, use CSS Modules or make sure every class name is unique in your project.
For details on how to use CSS Modules, see Adding a CSS Modules Stylesheet. You can also look at 9 Ways To Implement CSS in React JS for other available alternatives.
I recommend using unique class names. For example, lets say you have multiple ListView components: MemberUsersListView, AdminUsersListView, TestUsersListView; and each of them needs to be styled differently. I would create the following CSS classes:
.MUListView{
...
}
.AUListView{
...
}
.TUListView{
...
}
I know this seem's annoying, but it's cleaner than applying inline styles and easier to implement on smaller projects.
I created a simple React app using https://github.com/facebookincubator/create-react-app.
I am trying to specify a configurable URL to a component's CSS like this:
.Cell {
background-image: url({process.env.REACT_APP_STATIC_URL}./someImage.png);
}
And here's the component:
import React from 'react';
import './Cell.css'
class Cell extends React.Component {
render() {
return (
<div className="Cell">
{this.props.name}
</div>
);
}
}
But it doesn't look like the process variable trickles down to the imported CSS. How would I go about doing this?
If you want to use js variables in CSS, try React inline-style instead of plain css file.
https://facebook.github.io/react/tips/inline-styles.html
If you want to separate CSS and JS, you might need a CSS preprocessor to manage your global variables.
I came across one such scenario, The method I used is instead of adding it as background in CSS, make an img element and assign the path as src in component itself. I don't think there is any other way of doing that.
Commenting on this as I've recently had a similar issue. This should work to send an image file as a CSS variable in a build.
use the style prop to invoke a CSS style
Use template literal around the url() value
use the Javascript require() to refer to the file in the final build pack. Using a relative url requires that you call the image relative to where the the page will be called instead of being relative to the component JS file.
In the React component, use the inline style prop to set the CSS variable:
<div
style={{"--img":`url( ${require("../../images/coding.jpg")})`}}>
</div>
in the CSS file:
background-image: var(--img);
I am using css modules for my project, and I have a file positioning.css which has some useful classes that I want to import. e.g. .right, .left
What is the best approach for this using CSS Modules?
At the moment I can see 2 options, but they are not all that great:
composition in the component's style
.right {
composes: right from '../styles/positioning.css';
}
or
multiple css module imports in the component
import positioning from '../styles/positioning.css'
import styles from './myComponent.css';
Object.assign(styles, positioning)
class Menu extends Component {
render() {
return (
<div styleName='menu'>
<div styleName='left'>this is left</div>
<div styleName='right'>this is right</div>
</div>
);
}
};
export default CSSModules(Menu, styles);
I have manage to get this working:
// css file
#value class-to-compose from "file-where-class-is-defined.css";
.someclass {
composes: class-to-compose;
// other styles
}
One approach is to collect all app level css variables and calculations at the top level into app.css
#import "./theme/layout.css";
#import "./theme/colors.css";
...
Then reference app.css using
#import "../../app.css";
This way you can manage #import scope inside one file at the root level.
I'll go with the first proposition. (the result is quiet the same)
both proposition have quiet the same result
If someday you have to edit your Menu css, you'll just have to edit your Menu css and not your component.
You let CSSModules take decisions. (more futur proof?)
You could import the css files that you use frequently into a broader CSS file that you import on specific pages, this is taking the second approach but making it cleaner, especially if you have a lot of common core css files that you import on pretty much all pages.
I would advise you to go with [Sass] [1]. Sass allows for the usage of partials (i.e. distributed / scoped css sheets).
You write scoped (to the components you want) css and import all your partials into your main.css then.
Couple of other advantages:
you can do theming by having one partial that defines your them via variables, which you import first and then all your partials can use these variables.
having the css on a scoped level (at least to me) felt more "reactish" where components are supposed to be stand alone, but it also wasn't inline styling, which I find ugly and weird (I don't like to clutter down my .js files with styles)
[1] http://sass-lang.com/
I find this one line very helpful with importing:
#import 'file.css';
You could set these as globals and update their names to be a tad more semantic, like BootStraps pull-right.
If you declare them as
:global(.right) {
/* ... */
}
You can then just use them in your app by preferably importing globals early on in the entry point.
You should take a look at the option by vue.js component (scoped/overall)
You can choose a precompile css language like SASS, which can use #extend ...etc to reuse the common property, like below:
%common {
width: 100%;
height: inherit;
}
.my-class {
#extend %common;
}