ts-roots serves as a foundation for other libraries and applications to implement higher level abstractions of the Nostr protocol on top of it, including message transport, semantic event definitions, event storage mechanisms, and user interfaces.

ts-roots prioritizes correctness and clarity over optimization and efficiency. For high performance applications, it is recommended to implement optimizations in a separate library or in the application which requires them.

Installation

Add ts-roots to your project:

npm install @wisehodl/roots

Import it:

import * as events from '@wisehodl/roots/events';
import * as filters from '@wisehodl/roots/filters';
import * as keys from '@wisehodl/roots/keys';
import * as constants from '@wisehodl/roots/constants';
import * as errors from '@wisehodl/roots/errors';

import type { Event } from '@wisehodl/roots/events';
import type { Filter } from '@wisehodl/roots/filters';

Usage Examples

Key Management

Generate a new keypair

const privateKey = keys.generatePrivateKey();
const publicKey = keys.getPublicKey(privateKey);

Derive public key from existing private key

const privateKey = "f43a0435f69529f310bbd1d6263d2fbf0977f54bfe2310cc37ae5904b83bb167";
const publicKey = keys.getPublicKey(privateKey);
// publicKey: "cfa87f35acbde29ba1ab3ee42de527b2cad33ac487e80cf2d6405ea0042c8fef"

Event Creation and Signing

Create and sign a complete event

// 1. Build the event structure
const event: Event = {
  pubkey: publicKey,
  created_at: Math.floor(Date.now() / 1000),
  kind: 1,
  tags: [
    ["e", "5c83da77af1dec6d7289834998ad7aafbd9e2191396d75ec3cc27f5a77226f36"],
    ["p", "91cf9b32f3735070f46c0a86a820a47efa08a5be6c9f4f8cf68e5b5b75c92d60"],
  ],
  content: "Hello, Nostr!",
  id: "",
  sig: "",
};

// 2. Compute the event ID
const id = events.getID(event);
event.id = id;

// 3. Sign the event
const sig = events.sign(id, privateKey);
event.sig = sig;

Serialize an event for ID computation

// Returns canonical JSON: [0, pubkey, created_at, kind, tags, content]
const serialized = events.serialize(event);

Compute event ID manually

const id = events.getID(event);
// Returns lowercase hex SHA-256 hash of serialized form

Event Validation

Validate complete event

// Checks structure, ID computation, and signature
try {
  events.validate(event);
} catch (err) {
  console.log(`Invalid event: ${err.message}`);
}

Validate individual aspects

// Check field formats and lengths
try {
  events.validateStructure(event);
} catch (err) {
  console.log(`Malformed structure: ${err.message}`);
}

// Verify ID matches computed hash
try {
  events.validateID(event);
} catch (err) {
  console.log(`ID mismatch: ${err.message}`);
}

// Verify cryptographic signature
try {
  events.validateSignature(event);
} catch (err) {
  console.log(`Invalid signature: ${err.message}`);
}

Event JSON

Marshal event to JSON

const jsonString = JSON.stringify(events.toJSON(event));
// Standard JSON.stringify works with events.toJSON()

Unmarshal event from JSON

const event = events.fromJSON(JSON.parse(jsonString));

// Validate after unmarshaling
try {
  events.validate(event);
} catch (err) {
  console.log(`Received invalid event: ${err.message}`);
}

Filter Creation

Basic filter with standard fields

const since = Math.floor(Date.now() / 1000) - (24 * 60 * 60);
const limit = 50;

const filter: Filter = {
  ids: ["abc123", "def456"],  // Prefix match
  authors: ["cfa87f35"],      // Prefix match
  kinds: [1, 6, 7],
  since: since,
  limit: limit,
};

Filter with tag conditions

const filter: Filter = {
  kinds: [1],
  tags: {
    e: ["5c83da77af1dec6d7289834998ad7aafbd9e2191396d75ec3cc27f5a77226f36"],
    p: ["91cf9b32f3735070f46c0a86a820a47efa08a5be6c9f4f8cf68e5b5b75c92d60"],
  },
};

Filter with extensions (custom fields)

// Extensions allow arbitrary JSON fields beyond the standard filter spec.
// For example, this is how to implement non-standard filters like 'search'.
const filter: Filter = {
  kinds: [1],
  extensions: {
    search: "bitcoin",
  },
};

// Extensions are preserved during marshal/unmarshal but ignored by matches().
// Storage/transport layers can inspect extensions to implement custom behavior.

Filter Matching

Match single event

const filter: Filter = {
  authors: ["cfa87f35"],
  kinds: [1],
};

if (filters.matches(filter, event)) {
  // Event satisfies all filter conditions
}

Filter event collection

const since = Math.floor(Date.now() / 1000) - (60 * 60);
const filter: Filter = {
  kinds: [1],
  since: since,
  tags: {
    p: ["abc123", "def456"],  // OR within tag values
  },
};

const matches = eventCollection.filter(event => filters.matches(filter, event));

Filter JSON

Marshal filter to JSON

const filter: Filter = {
  ids: ["abc123"],
  kinds: [1],
  tags: {
    e: ["event-id"],
  },
  extensions: {
    search: "nostr",
  },
};

const jsonString = JSON.stringify(filters.toJSON(filter));
// Result: {"ids":["abc123"],"kinds":[1],"#e":["event-id"],"search":"nostr"}

Unmarshal filter from JSON

const jsonData = `{
  "authors": ["cfa87f35"],
  "kinds": [1],
  "#e": ["abc123"],
  "since": 1234567890,
  "search": "bitcoin"
}`;

const filter = filters.fromJSON(JSON.parse(jsonData));

// Standard fields populated: authors, kinds, since
// Tag filters populated: tags.e = ["abc123"]
// Unknown fields populated: extensions.search = "bitcoin"

Extensions field behavior

The extensions field captures any JSON properties not recognized as standard filter fields or tag filters. This design allows the core library to remain frozen while storage and transport layers implement custom filtering behavior.

Standard fields: ids, authors, kinds, since, until, limit

Tag filters: Any key starting with # (e.g., #e, #p, #emoji)

Extensions: Everything else

During marshaling, extensions merge into the output JSON. During unmarshaling, unrecognized fields populate extensions. The matches() method ignores extensions, and the library expects higher protocol layers to implement their usage.

Example implementing search filter:

const filter: Filter = {
  kinds: [1],
  extensions: {
    search: "bitcoin",
  },
};

// In a storage layer (not this library):
if (filter.extensions?.search) {
  const searchTerm = filter.extensions.search as string;
  // Apply full-text search using searchTerm
}

Testing

This library contains a comprehensive suite of unit tests. Run them with:

npm test

Or for a single run:

npm run test:run