CSS Modules, React and Overriding CSS Classes

Question

I am using a React component library (React Toolbox), which is outputting this class in their Tab component using CSS Modules and Webpack: label___1nGy active___1Jur tab___Le7N The tab is a className prop I am passing down. The label and active classes are coming from the library. I want to apply a different set of styles on active, something like .tab.active where tab is referring to the styles I have created and active matches the generated selector the library has created but cannot figure out how to do this with css-modules. I need to override this dynamically selector: .label___1nGy.active___1Jur.

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Answer 1

Old post but still relevant, so adding an answer to help those with similar issue

While not inherently possible in CSS modules alone, the author of the react-toolbox library has actually solved this particular problem very nicely

Read their github docs which are more in depth on the subject at https://github.com/react-toolbox/react-toolbox#customizing-components

A list of the themeable classes for a particular component is given on the component demo page on their site too

In your case as well as passing a className for tab, you would also create a theme with classes that overrides that desired parts of the default theme and pass that as the theme prop. For example something alog the lines of...

MyComponentWithTabs.css

.tab {   color: white; } 

MyTabTheme.css

.active {   color: hotpink; } 

MyComponentWithTabs.js

import styles from './MyComponentWithTabs.css' import tabTheme from './MyTabTheme.css'  // blah blah...  return <Tab key={index} className={styles.tab} theme={tabTheme} /> 

Under the surface this uses a decorator they have abstracted into separate library react-css-themr, I recommend giving that a read too as it explains how the defaults are composed with your overrides in much greater depth, including the different merging strategies they use