chore: deduplicate all $set calls done from setPersonProperties

[joshsny]

Changes

Move deduplication of set events from identify to setPersonProperties which is used by other methods calling $set (e.g. people.$set, people.$set_once and .setPersonProperties)

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	Mar 21, 2025 11:28am

[greptile-apps]

PR Summary

This PR moves deduplication logic for $set calls from the identify function to setPersonProperties, centralizing the handling of person property updates across multiple methods.

• Renamed getIdentifyHash to getPersonPropertiesHash in src/utils/identify-utils.ts for better clarity
• Moved deduplication logic from identify to setPersonProperties to handle all $set calls in one place
• Renamed _cachedIdentify to _cachedPersonProperties in src/posthog-core.ts to reflect broader usage
• Added hash check and caching in setPersonProperties to prevent duplicate property updates

_{2 file(s) reviewed, 1 comment(s)
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[github-actions]

Size Change: +640 B (+0.02%)

Total Size: 3.6 MB

Filename	Size	Change
dist/array.full.es5.js	278 kB	+64 B (+0.02%)
dist/array.full.js	381 kB	+64 B (+0.02%)
dist/array.full.no-external.js	380 kB	+64 B (+0.02%)
dist/array.js	189 kB	+64 B (+0.03%)
dist/array.no-external.js	187 kB	+64 B (+0.03%)
dist/main.js	189 kB	+64 B (+0.03%)
dist/module.full.js	381 kB	+64 B (+0.02%)
dist/module.full.no-external.js	380 kB	+64 B (+0.02%)
dist/module.js	189 kB	+64 B (+0.03%)
dist/module.no-external.js	187 kB	+64 B (+0.03%)

ℹ️ View Unchanged

Filename	Size
dist/all-external-dependencies.js	220 kB
dist/customizations.full.js	14.1 kB
dist/dead-clicks-autocapture.js	14.5 kB
dist/exception-autocapture.js	9.94 kB
dist/external-scripts-loader.js	2.75 kB
dist/posthog-recorder.js	211 kB
dist/recorder-v2.js	115 kB
dist/recorder.js	115 kB
dist/surveys-preview.js	71.3 kB
dist/surveys.js	76.6 kB
dist/tracing-headers.js	1.76 kB
dist/web-vitals.js	10.4 kB

_{compressed-size-action}

[rafaeelaudibert]

This looks good, but there's a rogue log I'd love you to remove before we can merge this

[posthog-bot]

This PR hasn't seen activity in a week! Should it be merged, closed, or further worked on? If you want to keep it open, post a comment or remove the stale label – otherwise this will be closed in another week.

[posthog-bot]

This PR hasn't seen activity in a week! Should it be merged, closed, or further worked on? If you want to keep it open, post a comment or remove the stale label – otherwise this will be closed in another week.

[pauldambra]

👍

the implementation looks valid to me...

i think I don't know enough about person processing to think through potential impacts which is probably a team CDP thing

[pl]

thought: You might be at the mercy of browser engines here. The code relies on getPersonPropertiesHash which isn't really a hash function. AFAIK, there's nothing that guarantees the ordering of fields in the output of JSON.stringify, so you might get different results for the above two objects. Anyway, that just means that some events won't get deduplicated.

[joshsny]

Yeah I think that most implementations do maintain key order, but it isn't critical if they don't

Paul and Zachg approved, I'm hasppy