Subscribe
Subscribe is the operation of registering a consumer with an observable, publisher, or event source to receive values, errors, completion signals, or other notifications.
Spring in Action, Sixth Edition
subscribe is a Project Reactor operation that attaches a subscriber to a publisher and initiates signal consumption.
- How it is used
- Starts consumption of a Reactor Flux or Mono and handles values from reactive pipelines or WebClient requests.
- How deep it goes
- Explains consumer callbacks, error handling, and the underlying Subscriber signals; distinguishes subscribe() from subscribeOn() without detailing Reactor internals.
- Examples
- Uses a fruit Flux printed by a lambda, StepVerifier assertions, and a WebClient ingredient request with timeout and error handling.
- What you can do after
- Apply it via Reactor’s Flux and Mono to consume values, register error handlers, and start reactive pipelines.
Read how Spring in Action, Sixth Edition explains subscribe →
The Joy of JavaScript
subscribe is the operation that attaches a consumer to an observable or similar event source so emissions are delivered to that consumer.
- How it is used
- Attaches consumers to lazy observables so event, collection, or application-domain emissions begin reaching handlers.
- How deep it goes
- Defines callback handling and cancellation, then demonstrates producer cleanup; it stops short of a full operator library.
- Examples
- Uses random numbers, observable-lifted pairs, and a reactive blockchain that delivers existing and newly pushed blocks.
- What you can do after
- Operate/configure streams by registering next, error, and complete handlers and unsubscribing when delivery is no longer needed.
Pro Angular 16
The subscribe method registers callbacks or an observer with an observable to receive notifications for emitted values and other sequence events.
- How it is used
- Handles emitted values and sequence events from observables in HTTP work, recurring notifications, content queries, and output-property tests.
- How deep it goes
- Defines callback forms and demonstrates component, query-change, and testing uses, but does not cover subscription disposal.
- Examples
- Uses a 500-millisecond ticker, changing content queries, and mouse-event-driven EventEmitter tests.
- What you can do after
- Apply it via RxJS and Angular to react to values, query changes, and component output events.
Related concepts
- Subscriptionproduces · A subscription is an object or association representing an ongoing relationship through which a consumer receives updates or data from a source and may control that relationship.
- request messageuses · An HTTP request is a message sent by a client to a server that specifies a method and target and may include headers and a body.
- observablepart of · An observable is a source that emits a sequence of values or notifications over time to consumers that subscribe to it.
- combinatorused by · A combinator is a function or computational construct that combines, composes, or transforms smaller functions or computations into a larger operation.
- unsubscribecontrasts with · Unsubscribe is the operation of detaching a consumer, listener, or recipient from a subscription or event source so it no longer receives notifications.
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