[Solved] Given this interceptor code, what will be logged?class LogInterceptor implements NestInterceptor { intercept(context, next) { console.log('Before handler'); | NestJS

NestJS - Interceptors

Given this interceptor code, what will be logged?

class LogInterceptor implements NestInterceptor {
  intercept(context, next) {
    console.log('Before handler');
    return next.handle().pipe(tap(() => console.log('After handler')));
  }
}

ABefore handler logged before method, After handler logged after method

BOnly Before handler is logged

COnly After handler is logged

DNo logs appear because tap is not called

Step-by-Step Solution

Solution:

Step 1: Understand intercept method flow
Console logs 'Before handler' immediately before calling next.handle().
Step 2: Analyze tap operator effect
Tap runs after the observable completes, logging 'After handler'.
Final Answer:
Before handler logged before method, After handler logged after method -> Option A
Quick Check:
Logs before and after method = Before handler logged before method, After handler logged after method [OK]

Quick Trick: tap() runs after observable completes, logging post-handler [OK]

Common Mistakes:

Thinking tap runs before next.handle()
Assuming no logs because of async
Confusing order of logs

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Given this interceptor code, what will be logged?

Step 1: Understand intercept method flow

Step 2: Analyze tap operator effect

Final Answer:

Quick Check:

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