Improving script loading strategy #24939

janicklas-ralph · 2021-05-10T04:23:20Z

Feature

Follow up PR from the RFC #24938

PR changes default script loading strategy to used defer in <head> under an experimental flag: experimental.disableOptimizedLoading with the default set to true, use false to get the new behavior.

ijjk · 2021-05-12T08:58:15Z

Failing test suites

Commit: e70303c

test/integration/optimized-loading/test/index.test.js

Optimized loading > dev mode > should render the page
Optimized loading > dev mode > should not have JS preload links
Optimized loading > dev mode > should load scripts with defer in head
Optimized loading > dev mode > should render the page
Optimized loading > dev mode > should not have JS preload links
Optimized loading > dev mode > should load scripts with defer in head

Expand output

● Optimized loading › dev mode › should render the page

FetchError: request to http://localhost:38975/ failed, reason: connect ECONNREFUSED 127.0.0.1:38975

  at ClientRequest.<anonymous> (../node_modules/node-fetch/lib/index.js:1461:11)

● Optimized loading › dev mode › should not have JS preload links

FetchError: request to http://localhost:38975/ failed, reason: connect ECONNREFUSED 127.0.0.1:38975

  at ClientRequest.<anonymous> (../node_modules/node-fetch/lib/index.js:1461:11)

● Optimized loading › dev mode › should load scripts with defer in head

FetchError: request to http://localhost:38975/ failed, reason: connect ECONNREFUSED 127.0.0.1:38975

  at ClientRequest.<anonymous> (../node_modules/node-fetch/lib/index.js:1461:11)

● Optimized loading › dev mode › should render the page

FetchError: request to http://localhost:38975/page1 failed, reason: connect ECONNREFUSED 127.0.0.1:38975

  at ClientRequest.<anonymous> (../node_modules/node-fetch/lib/index.js:1461:11)

● Optimized loading › dev mode › should not have JS preload links

FetchError: request to http://localhost:38975/page1 failed, reason: connect ECONNREFUSED 127.0.0.1:38975

  at ClientRequest.<anonymous> (../node_modules/node-fetch/lib/index.js:1461:11)

● Optimized loading › dev mode › should load scripts with defer in head

FetchError: request to http://localhost:38975/page1 failed, reason: connect ECONNREFUSED 127.0.0.1:38975

  at ClientRequest.<anonymous> (../node_modules/node-fetch/lib/index.js:1461:11)

ijjk · 2021-05-12T18:52:22Z

Stats from current PR

Default Server Mode (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	janicklas-ralph/next.js script	Change
buildDuration	16.8s	16.7s	-141ms
buildDurationCached	4.9s	5s	⚠️ +21ms
nodeModulesSize	46.6 MB	46.6 MB	⚠️ +6.65 kB

Page Load Tests Overall increase ✓

	vercel/next.js canary	janicklas-ralph/next.js script	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.884	2.81	-0.07
/ avg req/sec	866.7	889.68	+22.98
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.704	1.716	⚠️ +0.01
/error-in-render avg req/sec	1466.97	1456.85	⚠️ -10.12

Client Bundles (main, webpack, commons)

	vercel/next.js canary	janicklas-ralph/next.js script	Change
framework-HASH.js gzip	39.3 kB	39.3 kB	✓
main-HASH.js gzip	19.4 kB	19.4 kB	✓
webpack-HASH.js gzip	994 B	994 B	✓
Overall change	59.7 kB	59.7 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	janicklas-ralph/next.js script	Change
polyfills-HASH.js gzip	31.1 kB	31.1 kB	✓
Overall change	31.1 kB	31.1 kB	✓

Client Pages

	vercel/next.js canary	janicklas-ralph/next.js script	Change
_app-HASH.js gzip	1.02 kB	1.02 kB	✓
_error-HASH.js gzip	3.06 kB	3.06 kB	✓
amp-HASH.js gzip	526 B	526 B	✓
css-HASH.js gzip	334 B	334 B	✓
hooks-HASH.js gzip	890 B	890 B	✓
index-HASH.js gzip	262 B	262 B	✓
link-HASH.js gzip	1.65 kB	1.65 kB	✓
routerDirect..HASH.js gzip	331 B	331 B	✓
withRouter-HASH.js gzip	329 B	329 B	✓
bb14e60e810b..30f.css gzip	125 B	125 B	✓
Overall change	8.54 kB	8.54 kB	✓

Client Build Manifests

	vercel/next.js canary	janicklas-ralph/next.js script	Change
_buildManifest.js gzip	390 B	390 B	✓
Overall change	390 B	390 B	✓

Rendered Page Sizes

	vercel/next.js canary	janicklas-ralph/next.js script	Change
index.html gzip	559 B	559 B	✓
link.html gzip	568 B	568 B	✓
withRouter.html gzip	556 B	556 B	✓
Overall change	1.68 kB	1.68 kB	✓

Serverless Mode (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	janicklas-ralph/next.js script	Change
buildDuration	20.6s	20.6s	-36ms
buildDurationCached	7.3s	7.4s	⚠️ +97ms
nodeModulesSize	46.6 MB	46.6 MB	⚠️ +6.65 kB

Client Bundles (main, webpack, commons)

	vercel/next.js canary	janicklas-ralph/next.js script	Change
framework-HASH.js gzip	39.3 kB	39.3 kB	✓
main-HASH.js gzip	19.4 kB	19.4 kB	✓
webpack-HASH.js gzip	994 B	994 B	✓
Overall change	59.7 kB	59.7 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	janicklas-ralph/next.js script	Change
polyfills-HASH.js gzip	31.1 kB	31.1 kB	✓
Overall change	31.1 kB	31.1 kB	✓

Client Pages

	vercel/next.js canary	janicklas-ralph/next.js script	Change
_app-HASH.js gzip	1.02 kB	1.02 kB	✓
_error-HASH.js gzip	3.06 kB	3.06 kB	✓
amp-HASH.js gzip	526 B	526 B	✓
css-HASH.js gzip	334 B	334 B	✓
hooks-HASH.js gzip	890 B	890 B	✓
index-HASH.js gzip	262 B	262 B	✓
link-HASH.js gzip	1.65 kB	1.65 kB	✓
routerDirect..HASH.js gzip	331 B	331 B	✓
withRouter-HASH.js gzip	329 B	329 B	✓
bb14e60e810b..30f.css gzip	125 B	125 B	✓
Overall change	8.54 kB	8.54 kB	✓

Client Build Manifests

	vercel/next.js canary	janicklas-ralph/next.js script	Change
_buildManifest.js gzip	390 B	390 B	✓
Overall change	390 B	390 B	✓

Serverless bundles Overall increase ⚠️

	vercel/next.js canary	janicklas-ralph/next.js script	Change
_error.js	1.34 MB	1.34 MB	⚠️ +1.47 kB
404.html	2.42 kB	2.42 kB	✓
500.html	2.41 kB	2.41 kB	✓
amp.amp.html	10.8 kB	10.8 kB	✓
amp.html	1.61 kB	1.61 kB	✓
css.html	1.79 kB	1.79 kB	✓
hooks.html	1.67 kB	1.67 kB	✓
index.js	1.34 MB	1.34 MB	⚠️ +1.47 kB
link.js	1.4 MB	1.4 MB	⚠️ +1.47 kB
routerDirect.js	1.39 MB	1.4 MB	⚠️ +1.47 kB
withRouter.js	1.39 MB	1.4 MB	⚠️ +1.47 kB
Overall change	6.9 MB	6.9 MB	⚠️ +7.37 kB

Webpack 4 Mode (Decrease detected ✓)

General Overall increase ⚠️

	vercel/next.js canary	janicklas-ralph/next.js script	Change
buildDuration	14.2s	14s	-214ms
buildDurationCached	6s	6s	-58ms
nodeModulesSize	46.6 MB	46.6 MB	⚠️ +6.65 kB

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	janicklas-ralph/next.js script	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.817	2.894	⚠️ +0.08
/ avg req/sec	887.56	863.81	⚠️ -23.75
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.576	1.684	⚠️ +0.11
/error-in-render avg req/sec	1585.82	1484.88	⚠️ -100.94

Client Bundles (main, webpack, commons)

	vercel/next.js canary	janicklas-ralph/next.js script	Change
677f882d2ed8..HASH.js gzip	13.3 kB	13.3 kB	✓
framework.HASH.js gzip	39 kB	39 kB	✓
main-HASH.js gzip	7.26 kB	7.26 kB	✓
webpack-HASH.js gzip	751 B	751 B	✓
Overall change	60.3 kB	60.3 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	janicklas-ralph/next.js script	Change
polyfills-HASH.js gzip	31.3 kB	31.3 kB	✓
Overall change	31.3 kB	31.3 kB	✓

Client Pages

	vercel/next.js canary	janicklas-ralph/next.js script	Change
_app-HASH.js gzip	1.28 kB	1.28 kB	✓
_error-HASH.js gzip	3.74 kB	3.74 kB	✓
amp-HASH.js gzip	536 B	536 B	✓
css-HASH.js gzip	339 B	339 B	✓
hooks-HASH.js gzip	887 B	887 B	✓
index-HASH.js gzip	227 B	227 B	✓
link-HASH.js gzip	1.64 kB	1.64 kB	✓
routerDirect..HASH.js gzip	303 B	303 B	✓
withRouter-HASH.js gzip	302 B	302 B	✓
e025d2764813..52f.css gzip	125 B	125 B	✓
Overall change	9.38 kB	9.38 kB	✓

Client Build Manifests

	vercel/next.js canary	janicklas-ralph/next.js script	Change
_buildManifest.js gzip	420 B	420 B	✓
Overall change	420 B	420 B	✓

Rendered Page Sizes

	vercel/next.js canary	janicklas-ralph/next.js script	Change
index.html gzip	614 B	614 B	✓
link.html gzip	620 B	620 B	✓
withRouter.html gzip	607 B	607 B	✓
Overall change	1.84 kB	1.84 kB	✓

Commit: c8842e0

Improving script loading strategy

e81926e

janicklas-ralph requested review from divmain, ijjk, lfades, shuding and timneutkens as code owners May 10, 2021 04:23

ijjk added the type: next label May 10, 2021

Fix unwanted change

862d419

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janicklas-ralph mentioned this pull request May 10, 2021

Refactor experimental-script component #24940

Merged

janicklas-ralph added 2 commits May 11, 2021 12:16

Merge branch 'canary' of github.com:vercel/next.js into script

e657f7b

Flip flag for minor release

6523bc2

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Refactor test name

88cd89e

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Update flag on next-server and worker

e70303c

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janicklas-ralph added 2 commits May 12, 2021 11:30

Merge branch 'canary' of github.com:vercel/next.js into script

79c5f9a

Fix test

c8842e0

timneutkens merged commit eaf74c1 into vercel:canary May 13, 2021

janicklas-ralph deleted the script branch May 25, 2021 20:37

flybayer pushed a commit to blitz-js/next.js that referenced this pull request Jun 1, 2021

Improving script loading strategy (vercel#24939)

cfb05e6

shuding mentioned this pull request Nov 12, 2021

Improve script loading when streaming is enabled #31338

Closed

vercel locked as resolved and limited conversation to collaborators Jan 28, 2022

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janicklas-ralph commented May 10, 2021 •

edited by timneutkens

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ijjk commented May 12, 2021

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ijjk commented May 12, 2021

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Improving script loading strategy #24939

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ijjk commented May 12, 2021

Failing test suites

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ijjk commented May 12, 2021

Stats from current PR

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janicklas-ralph commented May 10, 2021 •

edited by timneutkens

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