Next 14 build First Load JS size increased compared to Next 13.5.6

AnasArafeh commented 10 months ago

Link to the code that reproduces this issue

https://github.com/AnasArafeh/Next14-build-issue-reproduction

To Reproduce

npm install Next 13.5.6
npm run build
view first load js sizes
npm install Next 14.0.1
npm run build
view first load js sizes

Current vs. Expected behavior

Following the previous steps:

The result for npm run build in Next 13.5.6 : 13 5 6

And the result for npm run build in Next 14.0.1 : 14 0 1

the only package changes were these using git : git-changes

The result for Next 14.0.2-canary.12 : 14 0 2-canary 12

Screenshots from reproduction template

Next 13.5.6

reproduction-13 5 6

Next 14.0.2-canary.12

reproduction-canary 12

Verify canary release

[X] I verified that the issue exists in the latest Next.js canary release

Provide environment information

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 10 Enterprise
Binaries:
  Node: 18.18.0
  npm: N/A
  Yarn: N/A
  pnpm: N/A
Relevant Packages:
  next: 14.0.2-canary.12
  eslint-config-next: 14.0.1
  react: 18.2.0
  react-dom: 18.2.0
  typescript: 5.2.2
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

Package manager (npm, pnpm, Yarn), Script optimization (next/script)

Additional context

The issue was introduced in Next 14, I have also tested it on the latest canary release and the issue remains the same. I have even noticed 1 KB increase in canary release compared to Next 14.0.1.

_NEXT-1762

jantimon commented 10 months ago

maybe duplicate of #57886

abenhamdine commented 10 months ago

probably fixed by https://github.com/vercel/next.js/pull/57904

AnasArafeh commented 10 months ago

@jantimon @abenhamdine I have tried the latest canary release Next 14.0.2-canary.21 that I believe includes the fix mentioned.

There was a small decrease few kb as shown in screenshot

Next 14.0.2-canary.12

Next 14.0.2-canary.21

However, if you compare it to Next 13.5.6 ( screenshot available in the issue above ) you can see that the actual First Load JS size is doubled for some files, so these few KB changes does not resolve the issue.