Run prettier on output in build dirs (#5858)

CHANGELOG.md

@@ -64,8 +64,10 @@
 
 ### Chore & Maintenance
 
+* `[#5858]` Run Prettier on compiled output
+  ([#5858](https://github.com/facebook/jest/pull/3497))
 * `[#5708]` Add fileChange hook for plugins
-  ([#5648](https://github.com/facebook/jest/pull/5708))
+  ([#5708](https://github.com/facebook/jest/pull/5708))
 * `[docs]` Add docs on using `jest.mock(...)`
   ([#5648](https://github.com/facebook/jest/pull/5648))
 * `[docs]` Mention Jest Puppeteer Preset

integration-tests/__tests__/__snapshots__/failures.test.js.snap

@@ -116,7 +116,7 @@ exports[`works with async failures 1`] = `
     +   \\"foo\\": \\"bar\\",
       }
       
-      at packages/expect/build/index.js:104:76
+      at packages/expect/build/index.js:160:61
 
 "
 `;

integration-tests/__tests__/__snapshots__/globals.test.js.snap

@@ -32,7 +32,7 @@ exports[`cannot test with no implementation 1`] = `
       4 |     test('test, no implementation');
       5 |   
       
-      at packages/jest-jasmine2/build/jasmine/Env.js:390:15
+      at packages/jest-jasmine2/build/jasmine/Env.js:405:15
       at __tests__/only-constructs.test.js:3:5
 
 "
@@ -59,7 +59,7 @@ exports[`cannot test with no implementation with expand arg 1`] = `
       4 |     test('test, no implementation');
       5 |   
       
-      at packages/jest-jasmine2/build/jasmine/Env.js:390:15
+      at packages/jest-jasmine2/build/jasmine/Env.js:405:15
       at __tests__/only-constructs.test.js:3:5
 
 "

scripts/build.js

@@ -28,6 +28,7 @@ const mkdirp = require('mkdirp');
 const babel = require('babel-core');
 const chalk = require('chalk');
 const micromatch = require('micromatch');
+const prettier = require('prettier');
 const stringLength = require('string-length');
 const getPackages = require('./getPackages');
 const browserBuild = require('./browserBuild');
@@ -46,6 +47,8 @@ const transformOptions = JSON.parse(
   fs.readFileSync(path.resolve(__dirname, '..', '.babelrc'), 'utf8')
 );
 transformOptions.babelrc = false;
+const prettierConfig = prettier.resolveConfig.sync(__filename);
+prettierConfig.trailingComma = 'none';
 
 const adjustToTerminalWidth = str => {
   const columns = process.stdout.columns || 80;
@@ -161,7 +164,8 @@ function buildFile(file, silent) {
     }
 
     const transformed = babel.transformFileSync(file, options).code;
-    fs.writeFileSync(destPath, transformed);
+    const prettyCode = prettier.format(transformed, prettierConfig);
+    fs.writeFileSync(destPath, prettyCode);
     silent ||
       process.stdout.write(
         chalk.green('  \u2022 ') +