title: ReactJs map undefined in IE10
body: <p>i saw similar questions and tried everything but not helped. </p>
  
  <p>I'm getting error map is undefined in ie10 and ie11. 
  After making this changes on my project, ie11 worked but ie10 not. </p>
  
  <p>in my package.json: </p>
  
  <pre><code>"browserslist": {
      "production": [
        "&gt;0.2%",
        "not dead",
        "not op_mini all"
      ],
      "development": [
        "last 1 chrome version",
        "last 1 firefox version",
        "last 1 safari version",
        "ie 10",
        "ie 11"
      ]
    }
  </code></pre>
  
  <p>i have install <strong>core-js</strong> package from npm and i put in my top level of my app, App.js: </p>
  
  <pre><code>import 'react-app-polyfill/ie11';
  import 'react-app-polyfill/stable';
  import "core-js";
  import 'core-js/es/set'
  import 'core-js/es/map'
  </code></pre>
  
  <p>with these configuration my app works on ie11 but on ie10 not. What can i do ?</p>