1
Create a Generic Subscriber in RxJS
1m 25s
2
Extend Subscriber to Override `_next` in RxJS
1m 7s
3
Connect a Source to a Subscriber with RxJS `pipe`
3m 33s
4
Use `lift` to Connect a `source` to a `subscriber` in RxJS
1m 36s
5
Create a Reusable Operator from Scratch in RxJS
2m 5s
6
Create Operators from Existing Operators in RxJS
58s
7
Implement the `map` Operator from Scratch in RxJS
3m 5s
8
Chain RxJS Operators Together with a Custom `pipe` Function using Array.reduce
2m 19s
9
Implement RxJS `mergeMap` through inner Observables to Subscribe and Pass Values Through
5m 18s
10
Implement RxJS `switchMap` by Canceling Inner Subscriptions as Values are Passed Through
2m 7s
11
Implement RxJS `concatMap` by Waiting for Inner Subscriptions to Complete
5m 20s
12
`add` Inner Subscriptions to Outer Subscribers to `unsubscribe` in RxJS
2m 8s

Implement RxJS `switchMap` by Canceling Inner Subscriptions as Values are Passed Through

RxJS^6.0.0

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switchMap is mergeMap that checks for an "inner" subscription. If the "inner" subscription exists, switchMap unsubscribes from that "inner" subscription which effectively "cancels" any pending pushes.

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Build Your Own RxJS Pipeable Operators

J. Matthew

~ 5 years ago

Great explanation of switchMap!

My default Webpack build process breaks when I try to declare innerSubscription above the constructor. Seems like something is missing to handle that; not sure what or why. However, it's not necessary to declare the property. It is sufficient to reference and set this.innerSubscription inside _next. In fact, we're already doing that (working with an undeclared property) with this.fn.