Upgrade babel and core-js

This change also isolates the nested dependencies of the react-scripts package used in the builder, which were previously causing dependency conflicts, and fixes a flaky test

package.json

@@ -37,6 +37,8 @@
       "lab.js/sinon",
       "lab.js/sinon/**",
       "lab.js.builder/bootstrap",
+      "lab.js.builder/react-scripts",
+      "lab.js.builder/react-scripts/**",
       "lab.js.website/bootstrap"
     ]
   }

packages/library/package.json

@@ -12,10 +12,9 @@
   "main": "dist/lab.js",
   "module": "src/index.js",
   "dependencies": {
-    "@babel/runtime": "^7.1.2",
-    "babel-polyfill": "^6.23.0",
+    "@babel/runtime": "^7.7.0",
     "common-tags": "^1.8.0",
-    "core-js": "^2.5.6",
+    "core-js": "^3.6.1",
     "cross-env": "^5.2.0",
     "es2015-proxy": "^0.1.7",
     "es6-promise": "^4.1.0",
@@ -30,15 +29,15 @@
     "whatwg-fetch": "^2.0.4"
   },
   "devDependencies": {
-    "@babel/core": "^7.1.0",
-    "@babel/plugin-proposal-class-properties": "^7.1.0",
+    "@babel/core": "^7.7.0",
+    "@babel/plugin-proposal-class-properties": "^7.7.0",
     "@babel/plugin-proposal-nullish-coalescing-operator": "^7.7.4",
-    "@babel/plugin-proposal-object-rest-spread": "^7.0.0",
-    "@babel/plugin-transform-regenerator": "^7.0.0",
-    "@babel/plugin-transform-runtime": "^7.1.0",
-    "@babel/preset-env": "^7.1.0",
+    "@babel/plugin-proposal-object-rest-spread": "^7.7.0",
+    "@babel/plugin-transform-regenerator": "^7.7.0",
+    "@babel/plugin-transform-runtime": "^7.7.0",
+    "@babel/preset-env": "^7.7.0",
     "babel-eslint": "^9.0.0",
-    "babel-loader": "^8.0.0",
+    "babel-loader": "8.0.4",
     "babel-plugin-istanbul": "^5.1.0",
     "babel-plugin-lodash": "^3.2.6",
     "babel-preset-minify": "^0.5.0",

packages/library/src/index.js

@@ -1,5 +1,5 @@
-// Polyfill
-import 'babel-polyfill'
+// Load standard library polyfill
+import 'core-js/stable'
 
 // Components
 import { Component, Dummy } from './core'

packages/library/test/flow.js

@@ -303,11 +303,12 @@ describe('Flow control', () => {
       const a = new lab.core.Dummy()
       s.options.content = [a]
 
-      let error
-
       return s.run().then(() => {
-        s.step().catch(err => (error = err))
-      }).then(() => {
+        // Step beyond last sequence content, resolve error
+        // TODO: Extracting the error message here is not nice --
+        // it would be nicer to use chai-as-promised and assert.isRejected
+        return new Promise(resolve => s.step().catch(resolve))
+      }).then(error => {
         assert.equal(
           error.message,
           'Sequence ended, can\'t take any more steps'

packages/library/webpack.config.js

@@ -42,6 +42,7 @@ module.exports = (env, argv) => {
           // Module generation is handled by webpack
           modules: false,
           useBuiltIns: 'usage',
+          corejs: 3,
         }],
       ],
       plugins: [
@@ -74,6 +75,7 @@ module.exports = (env, argv) => {
           // Module generation is handled by webpack
           modules: false,
           useBuiltIns: 'usage',
+          corejs: 3,
         }],
       ],
       plugins: [