WIP trying things to get babel/IE to work

.babelrc

 {
-  "presets": ["@babel/preset-env", "@babel/preset-react"],
+  "presets": [
+    [
+      "@babel/preset-env",
+      {
+        "useBuiltIns": "entry",
+        "corejs": 3,
+        "forceAllTransforms": true
+      }
+    ],
+    "@babel/preset-react"
+  ],
   "plugins": [
     "@babel/plugin-transform-runtime",
+    "@babel/plugin-transform-arrow-functions",
     "transform-react-remove-prop-types",
     ["lodash", { "id": [
       "lodash",

package.json

@@ -27,6 +27,7 @@
     "Drew Winget <scipioaffricanus@gmail.com> (https://aeschylus.net/)",
     "Jack Reed <phillipjreed@gmail.com> (https://www.jack-reed.com)"
   ],
+  "browserList": "> 0.25%, not dead",
   "repository": "https://github.com/ProjectMirador/mirador",
   "dependencies": {
     "@material-ui/core": "^4.2.2",
@@ -72,7 +73,9 @@
   "devDependencies": {
     "@babel/cli": "^7.5.0",
     "@babel/core": "^7.5.0",
+    "@babel/plugin-transform-arrow-functions": "^7.2.0",
     "@babel/plugin-transform-runtime": "^7.5.0",
+    "@babel/polyfill": "^7.7.0",
     "@babel/preset-env": "^7.5.0",
     "@babel/preset-react": "^7.0.0",
     "babel-eslint": "10.0.2",
@@ -84,6 +87,7 @@
     "chalk": "^2.4.2",
     "codecov": "^3.5.0",
     "concurrently": "^4.1.1",
+    "core-js": "^3.4.1",
     "css-loader": "^3.0.0",
     "enzyme": "^3.10.0",
     "enzyme-adapter-react-16": "^1.14.0",
@@ -112,6 +116,8 @@
     "style-loader": "^0.23.1",
     "supertest": "^4.0.2",
     "terser-webpack-plugin": "^1.3.0",
+    "unfetch": "^4.1.0",
+    "url-polyfill": "^1.1.7",
     "webpack": "^4.35.3",
     "webpack-cli": "^3.3.5"
   },