BEM is methodology for maintainable and meaningful markup process. See more at bem.info
Bemixin provides React mixin for comfortable work with classnames. Please see examples in the test folder.
Similiar projects: https://github.com/azproduction/b_ https://github.com/albburtsev/bem-cn
They are very mature well-documented tools. Their overall functionality may suit you. Bemixin, on the other hand, has a different purpose. The main idea of Bemixin is to use internal state of a React component during classname constructing. Going this way we are implicit in our code:
If component returns
<div className={this.b_('_modificator')}>JustBlock</div>
we can change its classname by renaming the component name itself. Also, Bemixin uses a component state for toggling modificators. Again, please see examples in the test folder.