User properties in Firebase - Step-by-Step Execution

Process Flow - User properties

User opens app

↓

App collects user data

↓

Set user properties

↓

Properties sent to Firebase Analytics

↓

Firebase stores properties

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Properties used for analysis and targeting

User properties are labels set by the app to describe users. These are sent to Firebase Analytics to help understand and target users.

Execution Sample

Firebase

firebase.analytics().setUserProperties({
  favorite_food: 'pizza',
  user_level: 'gold'
});

This code sets two user properties: favorite_food and user_level for the current user.

Process Table

Step	Action	User Properties State	Firebase Analytics State
1	App starts, no user properties set	{}	{}
2	Call setUserProperties with favorite_food='pizza'	{"favorite_food":"pizza"}	{"favorite_food":"pizza"}
3	Call setUserProperties with user_level='gold'	{"favorite_food":"pizza", "user_level":"gold"}	{"favorite_food":"pizza", "user_level":"gold"}
4	User properties sent to Firebase Analytics backend	{"favorite_food":"pizza", "user_level":"gold"}	{"favorite_food":"pizza", "user_level":"gold"}
5	Properties stored and ready for analysis	{"favorite_food":"pizza", "user_level":"gold"}	{"favorite_food":"pizza", "user_level":"gold"}

💡 User properties are set and synced with Firebase Analytics for use in reports and targeting.

Status Tracker

Variable	Start	After Step 2	After Step 3	Final
userProperties	{}	{"favorite_food":"pizza"}	{"favorite_food":"pizza", "user_level":"gold"}	{"favorite_food":"pizza", "user_level":"gold"}
FirebaseAnalyticsState	{}	{"favorite_food":"pizza"}	{"favorite_food":"pizza", "user_level":"gold"}	{"favorite_food":"pizza", "user_level":"gold"}

Key Moments - 3 Insights

Why do user properties appear empty before calling setUserProperties?

Before calling setUserProperties, no properties are set, so the state is empty as shown in step 1 of the execution_table.

Can user properties be updated or overwritten?

Yes, calling setUserProperties again with the same property name updates its value, as shown when user_level is added in step 3.

Are user properties immediately available in Firebase Analytics reports?

Properties are sent and stored after setting, but reports may take some time to reflect changes, as indicated in steps 4 and 5.

Visual Quiz - 3 Questions

Look at the execution_table, what is the userProperties state after step 2?

A {"user_level":"gold"}

B {"favorite_food":"pizza"}

C {}

D {"favorite_food":"pizza", "user_level":"gold"}

💡 Hint

Check the 'User Properties State' column in row for step 2.

At which step are both favorite_food and user_level set in Firebase Analytics?

A Step 1

B Step 2

C Step 3

D Step 5

💡 Hint

Look for when both properties appear together in the 'Firebase Analytics State' column.

If you call setUserProperties again with favorite_food='sushi', what happens to userProperties?

A favorite_food changes to 'sushi', user_level stays 'gold'

B Both favorite_food and user_level are removed

C No change to userProperties

D user_level changes to 'sushi'

💡 Hint

User properties update existing keys when set again, as shown between steps 2 and 3.

Concept Snapshot

User properties label users with key-value pairs.
Set them using setUserProperties in Firebase Analytics.
Properties update or add to existing ones.
Used for user segmentation and analysis.
Changes sync to Firebase backend for reports.

Full Transcript

User properties in Firebase Analytics are labels that describe users with key-value pairs. When the app starts, no properties exist. Calling setUserProperties adds or updates these properties. For example, setting favorite_food to pizza adds that property. Adding user_level as gold adds another property. These properties are sent to Firebase Analytics backend and stored for analysis and targeting. Properties can be updated by calling setUserProperties again with the same keys. Reports may take time to reflect changes. This process helps understand user behavior and personalize experiences.

Practice

1. What is the main purpose of user properties in Firebase Analytics?

easy

A. To store simple information about users for better app insights

B. To authenticate users securely

C. To send push notifications to users

D. To manage database access rules

Solution

1. Step 1: Understand user properties role

   User properties are used to store simple info about users, like preferences or demographics.

2. Step 2: Differentiate from other Firebase features

   Authentication, notifications, and database rules serve different purposes unrelated to user properties.

3. Final Answer:

   To store simple information about users for better app insights -> Option A

4. Quick Check:

   User properties = store user info for insights [OK]

Hint: User properties = user info for insights, not security or messaging [OK]

Common Mistakes:

• Confusing user properties with authentication
• Thinking user properties send notifications
• Mixing user properties with database rules

2. Which of the following is the correct way to set a user property named favorite_color to blue in Firebase Analytics?

easy

A. firebase.analytics().setUserProperty('favorite_color', 'blue');

B. firebase.analytics().setUserProperties('favorite_color', 'blue');

C. firebase.analytics().setUserProperties({favorite_color: 'blue'});

D. firebase.analytics().setUserProperty({favorite_color: 'blue'});

Solution

1. Step 1: Recall correct method signature

   The correct method to set multiple user properties is setUserProperties with an object of key-value pairs.

2. Step 2: Check method usage

   firebase.analytics().setUserProperties({favorite_color: 'blue'}); uses setUserProperties with an object, which is correct. The other options misuse method names or parameters.

3. Final Answer:

   firebase.analytics().setUserProperties({favorite_color: 'blue'}); -> Option C

4. Quick Check:

   Use setUserProperties with object = firebase.analytics().setUserProperties({favorite_color: 'blue'}); [OK]

Hint: Use setUserProperties with an object for key-value pairs [OK]

Common Mistakes:

• Using setUserProperty instead of setUserProperties
• Passing key and value as separate arguments incorrectly
• Passing an object to setUserProperty

3. Consider this code snippet:

firebase.analytics().setUserProperties({membership: 'gold'});
console.log(userProperties.membership);

What will be the output of console.log?

medium

A. 'gold'

B. undefined

C. null

D. Error: userProperties is not defined

Solution

1. Step 1: Analyze variable usage

   The code calls setUserProperties but tries to log userProperties.membership.

2. Step 2: Check if userProperties is defined

   No variable named userProperties is declared or imported, so accessing it causes a ReferenceError.

3. Final Answer:

   Error: userProperties is not defined -> Option D

4. Quick Check:

   Undefined variable access = ReferenceError [OK]

Hint: User properties set in Firebase, not accessible as local variable [OK]

Common Mistakes:

• Assuming userProperties is a local object
• Expecting immediate local access after setUserProperties call
• Confusing Firebase API with local variables

4. You wrote this code to set a user property:

firebase.analytics().setUserProperties('plan', 'premium');

But it does not work. What is the error?

medium

A. The method name should be setUserProperty (singular)

B. setUserProperties expects an object, not two string arguments

C. User property keys cannot be strings

D. Firebase Analytics does not support user properties

Solution

1. Step 1: Review method signature

   setUserProperties requires a single object argument with key-value pairs, not separate strings.

2. Step 2: Identify correct usage

   Passing two strings causes the method to fail because it expects an object like {plan: 'premium'}.

3. Final Answer:

   setUserProperties expects an object, not two string arguments -> Option B

4. Quick Check:

   setUserProperties needs object argument [OK]

Hint: setUserProperties takes one object, not separate strings [OK]

Common Mistakes:

• Passing key and value as separate arguments
• Using wrong method name
• Thinking keys can't be strings

5. You want to track users by their subscription tier and preferred language using user properties. Which code snippet correctly sets both properties at once?

hard

A. firebase.analytics().setUserProperties({subscription: 'premium', language: 'en'});

B. firebase.analytics().setUserProperties('subscription', 'premium');
firebase.analytics().setUserProperties('language', 'en');

C. firebase.analytics().setUserProperty({subscription: 'premium', language: 'en'});

D. firebase.analytics().setUserProperties(['subscription', 'premium'], ['language', 'en']);

Solution

1. Step 1: Understand setting multiple properties

   To set multiple user properties at once, pass a single object with all key-value pairs to setUserProperties.

2. Step 2: Evaluate each option

   firebase.analytics().setUserProperties({subscription: 'premium', language: 'en'}); correctly uses an object with both properties. firebase.analytics().setUserProperties('subscription', 'premium'); firebase.analytics().setUserProperties('language', 'en'); incorrectly calls the method twice with wrong argument types. firebase.analytics().setUserProperty({subscription: 'premium', language: 'en'}); uses wrong method name. firebase.analytics().setUserProperties(['subscription', 'premium'], ['language', 'en']); passes arrays instead of an object.

3. Final Answer:

   firebase.analytics().setUserProperties({subscription: 'premium', language: 'en'}); -> Option A

4. Quick Check:

   One object with all properties = firebase.analytics().setUserProperties({subscription: 'premium', language: 'en'}); [OK]

Hint: Set multiple properties in one object with setUserProperties [OK]

Common Mistakes:

• Calling setUserProperties multiple times with wrong args
• Using setUserProperty instead of setUserProperties
• Passing arrays instead of an object