You want to transform a stream of user objects to only their email addresses, but only if the user is active. Which operator chain correctly achieves this?

hard🚀 Application Q8 of 15

Angular - RxJS Operators

Asource.pipe(map(u => u.email), filter(email => email.active))

Bsource.pipe(map(u => u.active), filter(active => active.email))

Csource.pipe(filter(u => u.active), map(u => u.email))

Dsource.pipe(filter(u => u.email), map(u => u.active))

Step-by-Step Solution

Solution:

Step 1: Filter active users first
Filter operator should check if user is active.
Step 2: Map to extract email
After filtering, map extracts the email property.
Final Answer:
source.pipe(filter(u => u.active), map(u => u.email)) -> Option C
Quick Check:
Filter active then map email = B [OK]

Quick Trick: Filter first, then map to transform data [OK]

Common Mistakes:

MISTAKES

Mapping before filtering
Filtering on wrong property
Swapping map and filter order

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More Angular Quizzes

You want to transform a stream of user objects to only their email addresses, but only if the user is active. Which operator chain correctly achieves this?

Step 1: Filter active users first

Step 2: Map to extract email

Final Answer:

Quick Check:

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