react-breakpoints/es/utils/index.js

A library that allows you to mount/unmount components depending on the viewport size. Welcome to the next level of responsive React applications.

export function stripUnit(value) {
  var unitlessValue = parseFloat(value);
  if (isNaN(unitlessValue)) return value;
  return unitlessValue;
}

export function em(pxValue) {
  var unitlessValue = stripUnit(pxValue);
  return unitlessValue / 16 + "em";
}