Add numeric separator support (#7817)

Author: tharun208

packages/babel-preset-react-app/create.js

@@ -154,6 +154,8 @@ module.exports = function(api, opts, env) {
           loose: true,
         },
       ],
+      // Adds Numeric Seperators
+      require('@babel/plugin-proposal-numeric-separator').default,
       // The following two plugins use Object.assign directly, instead of Babel's
       // extends helper. Note that this assumes `Object.assign` is available.
       // { ...todo, completed: true }

packages/babel-preset-react-app/package.json

@@ -24,6 +24,7 @@
     "@babel/core": "7.6.4",
     "@babel/plugin-proposal-class-properties": "7.5.5",
     "@babel/plugin-proposal-decorators": "7.6.0",
+    "@babel/plugin-proposal-numeric-separator": "7.2.0",
     "@babel/plugin-proposal-object-rest-spread": "7.6.2",
     "@babel/plugin-syntax-dynamic-import": "7.2.0",
     "@babel/plugin-transform-destructuring": "7.6.0",

packages/react-dev-utils/browsersHelper.js

@@ -42,7 +42,7 @@ function shouldSetBrowsers(isInteractive) {
 }
 
 function checkBrowsers(dir, isInteractive, retry = true) {
-  const current = browserslist.loadConfig({path: dir});
+  const current = browserslist.loadConfig({ path: dir });
   if (current != null) {
     return Promise.resolve(current);
   }