old_contents: const loaderUtils = require('loader-utils');
  const defaultOptions = {
    fileMap: '{fileName}',
  };
  module.exports = function(content) {
    this.cacheable();
    const options = Object.assign(
      {},
      defaultOptions,
      loaderUtils.getOptions(this)
    );
  
    return content + `
      if(module.hot) {
        // ${Date.now()}
        const cssReload = require(${loaderUtils.stringifyRequest(this, require.resolve('./hotModuleReplacement'))})(module.id, ${JSON.stringify(options)});
        module.hot.dispose(cssReload);
        module.hot.accept(undefined, cssReload);
      }
    `;
  };
  
new_contents: const loaderUtils = require('loader-utils');
  const defaultOptions = {
    fileMap: '{fileName}',
  };
  module.exports = function(content) {
    this.cacheable();
    const options = Object.assign(
      {},
      defaultOptions,
      loaderUtils.getOptions(this)
    );
  
    return content + `
      if(module.hot) {
        // ${Date.now()}
        var cssReload = require(${loaderUtils.stringifyRequest(this, require.resolve('./hotModuleReplacement'))})(module.id, ${JSON.stringify(options)});
        module.hot.dispose(cssReload);
        module.hot.accept(undefined, cssReload);
      }
    `;
  };
  
subject: Use var instead of const for IE10