How To Handle CSS Precedence When Using React And CSS Classes?

CSS precedence can be a tricky issue to deal with, especially when working with React and multiple CSS classes.

In this article, we’ll go over some of the ways you can handle CSS precedence to ensure that your styles are being applied correctly, along with code examples to illustrate each technique.

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Using !important Declaration.

One way to handle CSS precedence is to use the !important declaration. This will force a style to be applied no matter what other styles may be conflicting with it. Here’s an example:

.red-text {
  color: red !important;
}

In this example, the color style will be applied to any element with the red-text class, even if there are other styles that are conflicting with it. However, it’s generally considered bad practice to use !important excessively, as it can make your code more difficult to maintain and can also make it harder to override styles in the future.

Using pseudo-classes

Another way to handle CSS precedence is to use more specific selectors. In CSS, the more specific a selector is, the higher its precedence will be. For example, a style applied to an element with an ID will take precedence over a style applied to an element with a class.

You can also use attribute selectors and pseudo-classes to increase the specificity of your selectors. Here’s an example:

#main-header {
  font-size: 32px;
}

.secondary-header {
  font-size: 24px;
}

In this example, the font-size style applied to the element with the main-header ID will take precedence over the font-size style applied to elements with the secondary-header class, because the ID selector is more specific.

Using Inline Style

In React, you can also take advantage of the style prop to apply inline styles to your components.

Inline styles will always take precedence over styles applied with external stylesheets or with class names. Here’s an example:

<div style={{color: 'red'}}>
  This text will be red.
</div>

However, it’s generally considered a better practice to use external stylesheets and class names, as they can be more easily reused and managed.

Priority In CSS

It’s also important to keep in mind the order in which your styles are being applied. In general, styles that are defined later in your code will take precedence over those defined earlier.

This is because CSS is a cascading language, meaning that styles flow down from the parent element to the child elements. Here’s an example:

.red-text {
  color: red;
}

.blue-text {
  color: blue;
}

<div className="red-text blue-text">
  This text will be blue.
</div>

In this example, the blue-text class is defined after the red-text class, so its color the style will take precedence.

Finally, you can use the composes directive to specify that a style should be composed from multiple different sources.

This can be useful for creating more modular and reusable styles. Here’s an example:

.bold {
  font-weight: bold;
}

.red-text {
  color: red;
}

.bold-red-text {
  composes: bold, red-text
}

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