Applesauce

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Glossary ​

Event ​

A Nostr event defined in NIP-01 — the base unit of data in Nostr. An event has a kind, content, tags, created_at, pubkey, id, and sig.

Replaceable event ​

An event kind where a newer event from the same author overwrites the older one. Covers kinds 0, 3, and 10000–19999 as defined by NIP-01. Only the latest version is kept in the event store.

Addressable event ​

An event kind 30000–39999 that is replaced by pubkey + kind + d-tag rather than just pubkey + kind. Also called a "parameterized replaceable event". An author can publish many addressable events of the same kind as long as each has a distinct d tag.

Event pointer ​

A reference to a specific event — usually a { id, relays?, author? } shape or an nevent NIP-19 string. See NIP-19.

Profile pointer ​

A reference to a user — usually a { pubkey, relays? } shape or an nprofile NIP-19 string.

Address pointer ​

A reference to an addressable event — a { kind, pubkey, identifier, relays? } shape or an naddr NIP-19 string.

Signer ​

A class that follows the NIP-07 API — exposes getPublicKey(), signEvent(), and optionally nip04/nip44 encryption methods. The applesauce-signers package provides implementations for browser extensions, private keys, NIP-46 bunkers, NIP-49 encrypted keys, and more.

Helper method ​

A function that takes an event and returns some computed value from it. Helpers are pure, often memoized, and form the base layer most of the SDK is built on.

Event store ​

An in-memory database of events that can be subscribed to. Handles deduplication, replaceable-event replacement, and exposes reactive observables for filters and individual events. See Event Store.

Model ​

Computed state from the event store that can be subscribed to. A model is a function registered with eventStore.model(...) that turns one or more events into a reactive observable of derived data — a contact list, a profile, a timeline. See Models.

Cast ​

A typed class produced by castEvent or castUser that wraps a raw event or pubkey with both synchronous properties and reactive observable properties. Casts are the primary way UI code consumes Nostr data in Applesauce. See Casting System.

Observable ​

A lazy stream of values that is active when subscribed to. See RxJS Observables.

Chainable observable ​

An observable that exposes property accessors returning more observables, so you can dot-chain into nested reactive data (e.g. note.author.profile$.displayName) without manually composing RxJS operators. All $-suffixed properties on cast classes are chainable observables.

Factory ​

A chainable builder class for creating Nostr events. EventFactory and its subclasses (like NoteFactory) expose methods like .content(), .as(signer), and .sign() that compose event operations into a signed event. See Event Factory.

Operation ​

A reusable transform function in the factory pipeline. An event operation takes a draft event and returns a new draft; a tag operation takes a tag array and returns a new tag array. Operations are composed with eventPipe(...) and applied via .chain(...) or modifyPublicTags(...). See Event Operations and Tag Operations.

Action ​

An async function that runs a "read–modify–publish" cycle against an event store, signer, and publish method. Actions are executed with ActionRunner.run() or .exec() and cover common flows like follow, mute, bookmark, and list management. See Actions.

Loader ​

A stateful function that loads events from relays or a cache. Loaders handle batching, relay-hint routing, and caching so a single pubkey request becomes one relay query per batch window. See Loaders.

Upstream pool ​

The adapter interface loaders use to talk to a relay library. An UpstreamPool is either a (relays, filters) => Observable<Event> function or an object with a request method matching that signature — which lets Applesauce loaders work on top of applesauce-relay, nostr-tools' SimplePool, NDK, or Nostrify. See Upstream Pool.

NAST ​

Nostr Abstract Syntax Tree — the tree structure that applesauce-content parses a text note's content field into. Nodes represent text, mentions, hashtags, links, emojis, invoices, cashu tokens, galleries, and more. Renderers walk the tree to produce React, DOM, or plain-text output. See Content.

Encrypted content ​

The content field of an event that is encrypted using NIP-04 or NIP-44.

Hidden content ​

The content field that is encrypted by the signer to its own pubkey. Primarily used in NIP-51 lists to store private entries.

Hidden tags ​

An array of event tags stored inside the hidden content. Decrypted, parsed, and exposed alongside the event's public tags.