Update bundle analyzer readme

[ijjk]

Follow-up to #27463 this adds a note about installing as devDependency instead of changing the default install command as the plugin being a devDependency might cause issues unless wrapped in a process.env check.

Documentation / Examples

• Make sure the linting passes

[ijjk]

Stats from current PR

Default Build (Increase detected ⚠️)

General

	vercel/next.js canary	ijjk/next.js update/analyzer-readme	Change
buildDuration	15.6s	15.8s	⚠️ +160ms
buildDurationCached	3.6s	3.5s	-96ms
nodeModulesSize	50.3 MB	50.3 MB	✓

Page Load Tests Overall increase ✓

	vercel/next.js canary	ijjk/next.js update/analyzer-readme	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.606	2.581	-0.02
/ avg req/sec	959.35	968.73	+9.38
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.469	1.445	-0.02
/error-in-render avg req/sec	1702.08	1730.46	+28.38

Client Bundles (main, webpack, commons)

	vercel/next.js canary	ijjk/next.js update/analyzer-readme	Change
359.HASH.js gzip	2.96 kB	2.96 kB	✓
745.HASH.js gzip	180 B	180 B	✓
framework-HASH.js gzip	42.2 kB	42.2 kB	✓
main-HASH.js gzip	21 kB	21 kB	✓
webpack-HASH.js gzip	1.53 kB	1.53 kB	✓
Overall change	67.9 kB	67.9 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	ijjk/next.js update/analyzer-readme	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	ijjk/next.js update/analyzer-readme	Change
_app-HASH.js gzip	803 B	803 B	✓
_error-HASH.js gzip	3.06 kB	3.06 kB	✓
amp-HASH.js gzip	554 B	554 B	✓
css-HASH.js gzip	329 B	329 B	✓
dynamic-HASH.js gzip	2.52 kB	2.52 kB	✓
head-HASH.js gzip	2.28 kB	2.28 kB	✓
hooks-HASH.js gzip	903 B	903 B	✓
image-HASH.js gzip	5.63 kB	5.63 kB	✓
index-HASH.js gzip	261 B	261 B	✓
link-HASH.js gzip	1.66 kB	1.66 kB	✓
routerDirect..HASH.js gzip	319 B	319 B	✓
script-HASH.js gzip	387 B	387 B	✓
withRouter-HASH.js gzip	320 B	320 B	✓
bb14e60e810b..30f.css gzip	125 B	125 B	✓
Overall change	19.1 kB	19.1 kB	✓

Client Build Manifests

	vercel/next.js canary	ijjk/next.js update/analyzer-readme	Change
_buildManifest.js gzip	489 B	489 B	✓
Overall change	489 B	489 B	✓

Rendered Page Sizes

	vercel/next.js canary	ijjk/next.js update/analyzer-readme	Change
index.html gzip	531 B	531 B	✓
link.html gzip	542 B	542 B	✓
withRouter.html gzip	525 B	525 B	✓
Overall change	1.6 kB	1.6 kB	✓

---

Webpack 4 Mode (Decrease detected ✓)

General

	vercel/next.js canary	ijjk/next.js update/analyzer-readme	Change
buildDuration	12.5s	12.4s	-102ms
buildDurationCached	4.8s	4.8s	-48ms
nodeModulesSize	50.3 MB	50.3 MB	✓

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	ijjk/next.js update/analyzer-readme	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.641	2.624	-0.02
/ avg req/sec	946.45	952.92	+6.47
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.404	1.418	⚠️ +0.01
/error-in-render avg req/sec	1780.37	1762.83	⚠️ -17.54

Client Bundles (main, webpack, commons)

	vercel/next.js canary	ijjk/next.js update/analyzer-readme	Change
17.HASH.js gzip	2.98 kB	2.98 kB	✓
18.HASH.js gzip	185 B	185 B	✓
677f882d2ed8..HASH.js gzip	13.8 kB	13.8 kB	✓
framework.HASH.js gzip	41.9 kB	41.9 kB	✓
main-HASH.js gzip	8.4 kB	8.4 kB	✓
webpack-HASH.js gzip	1.22 kB	1.22 kB	✓
Overall change	68.5 kB	68.5 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	ijjk/next.js update/analyzer-readme	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	ijjk/next.js update/analyzer-readme	Change
_app-HASH.js gzip	791 B	791 B	✓
_error-HASH.js gzip	3.76 kB	3.76 kB	✓
amp-HASH.js gzip	552 B	552 B	✓
css-HASH.js gzip	333 B	333 B	✓
dynamic-HASH.js gzip	2.71 kB	2.71 kB	✓
head-HASH.js gzip	2.97 kB	2.97 kB	✓
hooks-HASH.js gzip	911 B	911 B	✓
index-HASH.js gzip	231 B	231 B	✓
link-HASH.js gzip	1.64 kB	1.64 kB	✓
routerDirect..HASH.js gzip	298 B	298 B	✓
script-HASH.js gzip	3.02 kB	3.02 kB	✓
withRouter-HASH.js gzip	294 B	294 B	✓
e025d2764813..52f.css gzip	125 B	125 B	✓
Overall change	17.6 kB	17.6 kB	✓

Client Build Manifests

	vercel/next.js canary	ijjk/next.js update/analyzer-readme	Change
_buildManifest.js gzip	500 B	500 B	✓
Overall change	500 B	500 B	✓

Rendered Page Sizes

	vercel/next.js canary	ijjk/next.js update/analyzer-readme	Change
index.html gzip	576 B	576 B	✓
link.html gzip	588 B	588 B	✓
withRouter.html gzip	569 B	569 B	✓
Overall change	1.73 kB	1.73 kB	✓

Commit: 11d5eb9

[loicraux]

Hi @ijjk !

You added the following comment to the README.md :

Note: if installing as a `devDependency` make sure to wrap the require in a `process.env` check as `next.config.js` is loaded during `next start` as well.

And you wrote that in your comment above :

the plugin being a devDependency might cause issues unless wrapped in a process.env check.

This is not very clear...

• Which issues could be caused by the plugin being a dev dependency ? When do these issues happen ? Even when the plugin is simply loaded w/ require, even if disabled ?

Could you provide an example of how to wrap the require call please, since in all examples of @next/bundle-analyzer usages I find on GitHub, the plugin is loaded during next start as well, but disabled with process.env.ANALYZE check

const withBundleAnalyzer = require('@next/bundle-analyzer')({
  enabled: process.env.ANALYZE === 'true',
});

module.exports = withBundleAnalyzer({ ...

I don't think this is what you recommend, correct me if I'm right ...

Thanks !