Feed

The feed system provides a powerful way to compose and load complex Nostr queries. It supports user scopes, web of trust filtering, DVM integration, and thread construction.

Controller

The controller.load() function is the main interface for fetching events from a feed. It handles all the complexity of relay selection, subscription management, and event filtering.

import {createFeedController} from '@welshman/app'
import {scopeFeed, wotFeed} from '@welshman/feeds'

const controller = createFeedController({
  // Define what to load
  feed: scopeFeed("follows"),

  // Optional configurations
  closeOnEose: true,     // Close after getting all events
  onEvent: event => {},  // Handle events as they arrive
  onEose: url => {},     // Handle EOSE from each relay
  onComplete: () => {},  // Called when all relays complete
})

// Load first 20 events
const events = await controller.load(20)

// Load next 20 events
const moreEvents = await controller.load(20)

The controller maintains its state between loads, so subsequent calls will:

• Continue from last position
• Use appropriate time windows
• Skip already seen events
• Maintain relay connections

Paginated Feed

import {intersectionFeed, scopeFeed, wotFeed} from '@welshman/feeds'

const HomeFeed = {
  let events = []
  let loading = false
  let controller

  onMount(() => {
    // Create feed for home timeline
    controller = createFeedController({
      feed: intersectionFeed(
        // Content from follows
        scopeFeed("follows"),
        // Filtered by web of trust
        wotFeed({min: 0.1})
      ),

      // Handle events as they arrive
      onEvent: event => {
        events = [...events, event]
      },

      // Track loading state
      onComplete: () => {
        loading = false
      }
    })

    // Initial load
    loadMore()
  })

  const loadMore = async () => {
    if (loading) return
    loading = true

    // Load next batch
    await controller.load(20)
  }
}

Key points about controller.load():

• Takes a limit parameter for batch size
• Returns a promise of loaded events
• Can be called repeatedly for pagination
• Handles subscription lifecycle
• Manages relay connections
• Deduplicates events

The controller is stateful and maintains:

• Current time window
• Seen events
• Active subscriptions
• Relay connections

This makes it ideal for implementing infinite scroll feeds, thread loading, and other paginated content scenarios.