@material-ui/core/es/styles/mergeClasses.js

React components that implement Google's Material Design.

import _objectSpread from "@babel/runtime/helpers/objectSpread";
import warning from 'warning';
import getDisplayName from '../utils/getDisplayName';

function mergeClasses(options = {}) {
  const {
    baseClasses,
    newClasses,
    Component,
    noBase = false
  } = options;

  if (!newClasses) {
    return baseClasses;
  }

  return _objectSpread({}, baseClasses, Object.keys(newClasses).reduce((accumulator, key) => {
    process.env.NODE_ENV !== "production" ? warning(baseClasses[key] || noBase || !newClasses[key], [`Material-UI: the key \`${key}\` ` + `provided to the classes property is not implemented in ${getDisplayName(Component)}.`, `You can only override one of the following: ${Object.keys(baseClasses).join(',')}`].join('\n')) : void 0;
    process.env.NODE_ENV !== "production" ? warning(!newClasses[key] || typeof newClasses[key] === 'string', [`Material-UI: the key \`${key}\` ` + `provided to the classes property is not valid for ${getDisplayName(Component)}.`, `You need to provide a non empty string instead of: ${newClasses[key]}.`].join('\n')) : void 0;

    if (newClasses[key]) {
      accumulator[key] = `${baseClasses[key]} ${newClasses[key]}`;
    }

    return accumulator;
  }, {}));
}

export default mergeClasses;