From 32c390a91937698557925270e7734eb20a932546 Mon Sep 17 00:00:00 2001
From: Joe Haddad <joe.haddad@zeit.co>
Date: Fri, 17 Jan 2020 13:12:29 -0500
Subject: [PATCH] Switch from `defer` to `async`

---
 packages/next/pages/_document.tsx              | 12 ++++++------
 test/integration/production/test/index.test.js |  6 +++---
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/packages/next/pages/_document.tsx b/packages/next/pages/_document.tsx
index 2134fc9aee8ae..5d63deda249b8 100644
--- a/packages/next/pages/_document.tsx
+++ b/packages/next/pages/_document.tsx
@@ -570,7 +570,7 @@ export class NextScript extends Component<OriginProps> {
 
       return (
         <script
-          defer
+          async
           key={bundle.file}
           src={`${assetPrefix}/_next/${encodeURI(
             bundle.file
@@ -611,7 +611,7 @@ export class NextScript extends Component<OriginProps> {
             file
           )}${_devOnlyInvalidateCacheQueryString}`}
           nonce={this.props.nonce}
-          defer
+          async
           crossOrigin={this.props.crossOrigin || process.crossOrigin}
           {...modernProps}
         />
@@ -720,7 +720,7 @@ export class NextScript extends Component<OriginProps> {
 
     const pageScript = [
       <script
-        defer
+        async
         data-next-page={page}
         key={page}
         src={
@@ -734,7 +734,7 @@ export class NextScript extends Component<OriginProps> {
       />,
       process.env.__NEXT_MODERN_BUILD && (
         <script
-          defer
+          async
           data-next-page={page}
           key={`${page}-modern`}
           src={
@@ -753,7 +753,7 @@ export class NextScript extends Component<OriginProps> {
 
     const appScript = [
       <script
-        defer
+        async
         data-next-page="/_app"
         src={
           assetPrefix +
@@ -767,7 +767,7 @@ export class NextScript extends Component<OriginProps> {
       />,
       process.env.__NEXT_MODERN_BUILD && (
         <script
-          defer
+          async
           data-next-page="/_app"
           src={
             assetPrefix +
diff --git a/test/integration/production/test/index.test.js b/test/integration/production/test/index.test.js
index 4c27b48eb34b7..141f96833e5dc 100644
--- a/test/integration/production/test/index.test.js
+++ b/test/integration/production/test/index.test.js
@@ -678,13 +678,13 @@ describe('Production Usage', () => {
     }
   })
 
-  it('should have defer on all script tags', async () => {
+  it('should have async on all script tags', async () => {
     const html = await renderViaHTTP(appPort, '/')
     const $ = cheerio.load(html)
     let missing = false
 
     for (const script of $('script').toArray()) {
-      // application/json doesn't need defer
+      // application/json doesn't need async
       if (
         script.attribs.type === 'application/json' ||
         script.attribs.src.includes('polyfills')
@@ -692,7 +692,7 @@ describe('Production Usage', () => {
         continue
       }
 
-      if (script.attribs.async === '' || script.attribs.defer !== '') {
+      if (script.attribs.defer === '' || script.attribs.async !== '') {
         missing = true
       }
     }