Rxjs tap 操作符的使用场景示例

import { of } from 'rxjs';
import { tap } from 'rxjs/operators';
of(1, 2, 3).pipe(
  tap(
    value => console.log(`TAPPED VALUE: ${value}`),
    error => console.error(`TAPPED ERROR: ${error}`),
    () => console.log('COMPLETED')
  )
).subscribe();

http.get('/api/data').pipe(
  tap(request => console.log(`Sending request: ${request}`)),
  // ... other operators to handle the response
  tap(response => console.log(`Received response: ${response}`))
).subscribe();

data$.pipe(
  tap(() => this.loading = true),  // Update loading status before data arrives
  // ... other operators to handle the data
  tap(() => this.loading = false)  // Update loading status after data arrives
).subscribe(data => this.updateUI(data));

data$.pipe(
  tap(data => {
    if (!isValid(data)) {
      throw new Error('Invalid data');
    }
  }),
  // ... other operators
).subscribe();