fix: improve survey bundle size v2

[lucasheriques]

Changes

Follow up to #1665 which I'll prob close.

I realized the method we were loading lazily, getSurveyNextStep was only really used inside the Surveys file (extension/surveys.tsx).

However, we were still loading it under the posthog-core.ts, which it doesn't really need.

So, instead of trying to load it individually lazily, I just added it to the main surveys extension file, and it can be loaded directly with that.

It also allows us to remove the old sdk / no branching logic, since, once they update their survey, everything will come from the surveys extension.

@pauldambra tagged you as my local posthog-js expert, let me know if this reasoning makes sense

Checklist

• Tests for new code (see advice on the tests we use)
• Accounted for the impact of any changes across different browsers
• Accounted for backwards compatibility of any changes (no breaking changes in posthog-js!)

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Name	Status	Preview	Updated (UTC)
posthog-js	✅ Ready (Inspect)	Visit Preview	Feb 22, 2025 4:20pm

[github-actions]

Size Change: -7.08 kB (-0.21%)

Total Size: 3.32 MB

Filename	Size	Change
dist/all-external-dependencies.js	218 kB	+1.5 kB (+0.69%)
dist/array.full.es5.js	270 kB	-231 B (-0.09%)
dist/array.full.js	373 kB	-209 B (-0.06%)
dist/array.full.no-external.js	372 kB	-209 B (-0.06%)
dist/array.js	183 kB	-1.71 kB (-0.93%)
dist/array.no-external.js	181 kB	-1.71 kB (-0.93%)
dist/main.js	183 kB	-2.05 kB (-1.11%)
dist/module.full.js	373 kB	-209 B (-0.06%)
dist/module.full.no-external.js	372 kB	-209 B (-0.06%)
dist/module.js	183 kB	-1.71 kB (-0.92%)
dist/module.no-external.js	182 kB	-1.71 kB (-0.93%)
dist/surveys-preview.js	70.1 kB	-123 B (-0.18%)
dist/surveys.js	74.9 kB	+1.49 kB (+2.03%)

ℹ️ View Unchanged

Filename	Size
dist/customizations.full.js	14 kB
dist/dead-clicks-autocapture.js	14.5 kB
dist/exception-autocapture.js	9.51 kB
dist/external-scripts-loader.js	2.64 kB
dist/recorder-v2.js	115 kB
dist/recorder.js	115 kB
dist/tracing-headers.js	1.76 kB
dist/web-vitals.js	10.4 kB

_{compressed-size-action}

[greptile-apps]

PR Summary

This PR optimizes bundle size by relocating survey-related logic from core files to the surveys extension.

• Moved getNextSurveyStep and getRatingBucketForResponseValue functions from posthog-core.ts to src/extensions/surveys.tsx
• Updated imports in src/entrypoints/surveys-preview.es.ts to reference functions directly from surveys extension
• Removed old SDK/branching logic since surveys will be loaded with the extension
• Consolidated survey-specific functionality in surveys.tsx to prevent unnecessary code loading
• Updated test imports in src/__tests__/surveys.test.ts to reflect new function locations

_{5 file(s) reviewed, 2 comment(s)
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[marandaneto]

assuming this is not breaking the frontend that depends on the next question for the survey preview, LGTM

[pauldambra]

since this is on posthog core could someone have integrated with it? should we keep the method and replace it instead with a deprecation log message, then replace it after some time?

(you all the experts on surveys so i may be worrying unnecessarily)

because of the lazy loading we always have to consider someone with posthog-js main bundle pre-this-change and latest lazy bundle

[lucasheriques]

should be fine, i checked for that! ran all e2e tests on posthog/posthog and did smoke tests for surveys extensively. didn't saw any other usage besides surveys' domain

[pauldambra]

one comment on how to think about avoiding breaking releases here but only to make sure you've thought about it 😊

otherwise, love this kind of analysis and CI is green 🙌