You want to create a simple store using BehaviorSubject to hold a user's profile object and update it safely. Which approach correctly updates only the user's name without losing other profile data?

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Angular - State Management

You want to create a simple store using BehaviorSubject to hold a user's profile object and update it safely. Which approach correctly updates only the user's name without losing other profile data?

const profile$ = new BehaviorSubject({ name: 'Alice', age: 30 });
// Update name to 'Bob' here

Aprofile$.next({ ...profile$.value, name: 'Bob' });

Bprofile$.next({ name: 'Bob' });

Cprofile$.value.name = 'Bob';

Dprofile$.update({ name: 'Bob' });

Step-by-Step Solution

Solution:

Step 1: Understand BehaviorSubject value update
Directly assigning to value property does not notify subscribers; next() must be called with full updated object.
Step 2: Preserve existing data while updating name
Use spread operator to copy existing profile and override name, then call next() with new object.
Step 3: Check other options
profile$.next({ name: 'Bob' }); loses age property; profile$.value.name = 'Bob'; mutates value without notification; profile$.update({ name: 'Bob' }); uses non-existent update() method.
Final Answer:
profile$.next({ ...profile$.value, name: 'Bob' }); -> Option A
Quick Check:
Use next() with spread to update partial data [OK]

Quick Trick: Use spread operator with next() to update partial store data [OK]

Common Mistakes:

Overwriting entire object losing other properties
Mutating value directly without next()
Using non-existent update() method

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You want to create a simple store using BehaviorSubject to hold a user's profile object and update it safely. Which approach correctly updates only the user's name without losing other profile data?

Step 1: Understand BehaviorSubject value update

Step 2: Preserve existing data while updating name

Step 3: Check other options

Final Answer:

Quick Check:

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