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Vue / Browser — Set person properties

Update user properties without changing the distinct ID. Use setPersonProperties to overwrite properties or setPersonPropertiesOnce to set them only if not already set.

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setPersonProperties(properties)

Sets or updates user properties (overwrites existing). Sends a $set event.
ParameterTypeRequiredDescription
propertiesRecord<string, unknown>yesUser properties to set or update
When to use: Update user properties after initial identification (e.g. plan changes, role updates, preference changes).

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setPersonPropertiesOnce(properties)

Sets user properties only if they are not already set. Sends a $set_once event.
ParameterTypeRequiredDescription
propertiesRecord<string, unknown>yesUser properties to set (only if not already set)
When to use: One-time attributes that shouldn’t be overwritten (e.g. signupSource, firstPurchaseDate, referralCode).

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Vue example

<script setup>
import { onMounted } from 'vue'
import { createSignal } from '@signal-js/browser'

let signal = null

onMounted(async () => {
  signal = createSignal({ endpoint: '...', apiKey: '...', projectId: '...' })
  await signal.start()
})

function updatePlan() {
  signal?.setPersonProperties({ plan: 'pro', role: 'admin' })
}

function setSignupSource() {
  // Only set if not already set
  signal?.setPersonPropertiesOnce({ signupSource: 'organic' })
}
</script>

<template>
  <div>
    <button @click="updatePlan">Upgrade Plan</button>
    <button @click="setSignupSource">Set Signup Source</button>
  </div>
</template>

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Vanilla JS example

const signal = createSignal({ endpoint: '...', apiKey: '...', projectId: '...' });
await signal.start();

// Update user plan
signal.setPersonProperties({ plan: 'enterprise', seats: 50 });

// Set signup source only if not already set
signal.setPersonPropertiesOnce({ signupSource: 'organic' });

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Differences from identify()

  • identify(distinctId, traits) — Changes the user’s distinct ID and sets properties. Use after login or when you know the user’s identity.
  • setPersonProperties(properties) — Updates properties without changing the distinct ID. Use when properties change after identification.
  • setPersonPropertiesOnce(properties) — Sets properties only if not already set. Use for immutable attributes.

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See also