How would I use `do` as an RxJS lettable operator?

Question

RxJS 5.5 allows grabbing lettable operators and piping them like so:

import { ajax } from 'rxjs/observable/dom/ajax'
import { catchError, map, retry } from 'rxjs/operators'

ajax.getJSON('https://example.com/api/test')
.pipe(
    retry(3, 1000),
    map(fetchUserFulfilled),
    catchError(console.error)
)

How would I use the do operator between these commands?

Answer 1

The do operator was renamed in RxJS 5.5 to tap because it collided with the JavaScript do keyword.

For more info see: https://github.com/ReactiveX/rxjs/blob/master/doc/pipeable-operators.md#pipeable-operators