Refrain from polyfilling until we know we want it

babel.config.js

@@ -17,20 +17,11 @@ module.exports = function(api) {
 
   return {
     presets: [
-      isTestEnv && [
-        require('@babel/preset-env').default,
-        {
-          targets: {
-            browsers: '> 1%',
-          },
-        },
-      ],
+      isTestEnv && [require('@babel/preset-env').default],
       (isProductionEnv || isDevelopmentEnv) && [
         require('@babel/preset-env').default,
         {
           forceAllTransforms: true,
-          useBuiltIns: 'usage',
-          corejs: '3.0.1',
           modules: false,
           exclude: ['transform-typeof-symbol'],
         },
@@ -39,8 +30,6 @@ module.exports = function(api) {
         require('@babel/preset-react').default,
         {
           development: isDevelopmentEnv || isTestEnv,
-          useBuiltIns: 'usage',
-          corejs: '3.0.1',
         },
       ],
     ].filter(Boolean),

package.json

@@ -13,14 +13,12 @@
   },
   "dependencies": {
     "@babel/core": "^7.4.3",
-    "@babel/polyfill": "^7.4.3",
     "@rails/actioncable": "^6.0.0-alpha",
     "@rails/activestorage": "^6.0.0-alpha",
     "@rails/ujs": "^6.0.0-alpha",
     "@rails/webpacker": "^4.0.2",
     "axios": "^0.18.0",
     "bootstrap": "^4.3.1",
-    "core-js": "^3.0.1",
     "prop-types": "^15.7.2",
     "react": "^16.8.6",
     "react-bootstrap": "^1.0.0-beta.8",

yarn.lock

@@ -615,7 +615,7 @@
     "@babel/helper-regex" "^7.4.3"
     regexpu-core "^4.5.4"
 
-"@babel/polyfill@^7.2.5", "@babel/polyfill@^7.4.3":
+"@babel/polyfill@^7.2.5":
   version "7.4.3"
   resolved "https://registry.yarnpkg.com/@babel/polyfill/-/polyfill-7.4.3.tgz#332dc6f57b718017c3a8b37b4eea8aa6eeac1187"
   integrity sha512-rkv8WIvJshA5Ev8iNMGgz5WZkRtgtiPexiT7w5qevGTuT7ZBfM3de9ox1y9JR5/OXb/sWGBbWlHNa7vQKqku3Q==
@@ -2395,7 +2395,7 @@ core-js-pure@3.0.1:
   resolved "https://registry.yarnpkg.com/core-js-pure/-/core-js-pure-3.0.1.tgz#37358fb0d024e6b86d443d794f4e37e949098cbe"
   integrity sha512-mSxeQ6IghKW3MoyF4cz19GJ1cMm7761ON+WObSyLfTu/Jn3x7w4NwNFnrZxgl4MTSvYYepVLNuRtlB4loMwJ5g==
 
-core-js@3.0.1, core-js@^3.0.1:
+core-js@3.0.1:
   version "3.0.1"
   resolved "https://registry.yarnpkg.com/core-js/-/core-js-3.0.1.tgz#1343182634298f7f38622f95e73f54e48ddf4738"
   integrity sha512-sco40rF+2KlE0ROMvydjkrVMMG1vYilP2ALoRXcYR4obqbYIuV3Bg+51GEDW+HF8n7NRA+iaA4qD0nD9lo9mew==