/formkit-core-skilld

Store and ledger

Messages

Each node owns a FormKitStore: a proxied map of FormKitMessage objects keyed by message key (dist/index.d.mts:118-136). Messages are immutable (Readonly<FormKitMessageProps>, dist/index.d.mts:70-75):

createMessage(conf?, node?) fills defaults: blocking: false, key: token(), meta: {}, type: 'state', visible: true (dist/index.d.mts:152-171).

Store traps

FormKitStoreTraps (dist/index.d.mts:142-150):

node.store.set(message)                 // add or replace by key
node.store.remove(key)                  // remove one
node.store.filter((m) => ..., type?)    // remove non-matching of type
node.store.reduce(reducer, initial)     // fold over messages
node.store.apply(messages, clear?)      // bulk, with optional child routing
node.store.release()                    // internal: drop child listeners
node.store.touch()                      // internal

Read/write cycle:

import { createMessage, createNode } from '@formkit/core'

const node = createNode()
node.store.set(createMessage({ key: 'clickHole', value: 'Click 100 times.' }))
node.store.clickHole.value   // 'Click 100 times.'

Setting, changing, or removing messages emits message-added, message-updated, message-removed — all bubble, so .deep listeners on an ancestor see subtree changes.

apply() and child routing

apply() accepts either a flat FormKitMessage[] (applied locally) or a FormKitInputMessages map where keys are child addresses (dist/index.d.mts:77-85,143). Messages for children that do not exist yet are buffered in _m and flushed when the matching child.deep event fires (dist/index.mjs:333-357). This is how setErrors targets nested inputs before they mount.

Ledger

The ledger counts messages matching a condition across a subtree (dist/index.d.mts:180-192). It wires message-added.deep / message-removed.deep listeners at init (dist/index.mjs:368-372) and merges child counters when children attach.

// establish a counter (returns a promise resolving after the initial count)
await node.ledger.count('visible', (m) => m.visible)

node.ledger.value('visible')     // current count
await node.ledger.settled('visible')  // resolves when the count returns to 0

Counters emit events you can watch instead of polling:

node.on('count:visible', ({ payload }) => { ... })
node.on('settled:blocking', () => { ... })

Condition shorthand: pass a string (a type such as 'validation') instead of a predicate — parseCondition expands it (dist/index.mjs:408-411).

Conventions:

• The validation plugin registers the blocking counter; forms query it to decide submitability (https://formkit.com/essentials/architecture#ledger).
• node.ledger.count() propagates the counter to existing children recursively, so register it once on the root (or any ancestor) (dist/index.mjs:401-404).
• settled(name) returns an already-resolved promise for unknown counter names (dist/index.mjs:374-376) — a typo silently never waits.