docs: setting up babel, fixes regeneratorRuntime not defined

CHANGELOG.md

@@ -171,6 +171,7 @@
 - `[diff-sequences]` Add performance benchmark to package ([#7603](https://github.com/facebook/jest/pull/7603))
 - `[*]` Replace as many `Object.assign` with object spread as possible ([#7627](https://github.com/facebook/jest/pull/7627))
 - `[ci]` Initial support for Azure Pipelines ([#7556](https://github.com/facebook/jest/pull/7556))
+- `[docs]` Changed Babel setup documentation to fix `async/await` ([#7701](https://github.com/facebook/jest/pull/7701))
 
 ### Performance
 

docs/GettingStarted.md

@@ -81,31 +81,65 @@ jest --init
 
 ### Using Babel
 
-To use [Babel](http://babeljs.io/), install the `babel-jest` and `@babel/core` packages via `yarn`:
+To use [Babel](http://babeljs.io/), install required dependencies via `yarn`:
 
 ```bash
-yarn add --dev babel-jest @babel/core
+yarn add --dev babel-jest @babel/core @babel/preset-env @babel/preset-react
 ```
 
-Don't forget to add a [`babel.config.js`](https://babeljs.io/docs/en/config-files) file in your project's root folder. For example, if you are using ES2018 and [React](https://reactjs.org) with the [`@babel/preset-env`](https://babeljs.io/docs/en/babel-preset-env) and [`@babel/preset-react`](https://babeljs.io/docs/en/babel-preset-react) presets:
+Configure Babel to target your current version of Node by creating a `babel.config.js` file in the root of your project:
 
-```js
+```javascript
+// babel.config.js
 module.exports = {
-  presets: ['@babel/preset-env', '@babel/preset-react'],
+  presets: [
+    [
+      '@babel/preset-env',
+      {
+        targets: {
+          node: 'current',
+        },
+      },
+    ],
+    '@babel/preset-react',
+  ],
 };
 ```
 
-You are now set up to use all ES2018 features and React-specific syntax.
+If you are not using React you can exclude `@babel/preset-react` from the above commands/config.
+
+The ideal configuration for Babel will depend on your project. See [Babel's docs](https://babeljs.io/docs/en/babel-preset-env) for more details.
+
+Jest will set `process.env.NODE_ENV` to 'test' if it's not set to something else, you can use that in your configuration to conditionally setup only the compilation needed for Jest, e.g.
+
+```javascript
+// babel.config.js
+module.exports =
+  process.env.NODE_ENV === 'test'
+    ? {
+        presets: [
+          [
+            '@babel/preset-env',
+            {
+              targets: {
+                node: 'current',
+              },
+            },
+          ],
+        ],
+      }
+    : {
+        // Configuration needed for production.
+      };
+```
 
 > Note: `babel-jest` is automatically installed when installing Jest and will automatically transform files if a babel configuration exists in your project. To avoid this behavior, you can explicitly reset the `transform` configuration option:
 
-```json
-// package.json
-{
-  "jest": {
-    "transform": {}
-  }
-}
+```javascript
+// jest.config.js
+module.exports = {
+  transform: {},
+};
 ```
 
 #### Babel 6