RunKit + npm: jss-increase-specificity

var jss = require('jss').default; var increaseSpecificity = require("jss-increase-specificity"); var preset = require('jss-preset-default').default; jss .setup(preset()) .use(increaseSpecificity()); const styles = { button: { fontSize: 12, }, }; console.log(jss.createStyleSheet(styles).toString());