Changelog

0.3.0

Minor Changes

de1c8a7: createYjsBackend returns a YjsBackend, a CrdtBackend with two more members: map, the synced Y.Map, and origin, which tags every transaction its write runs. Track that origin with Y.UndoManager to undo and redo the store's own edits:
```
const backend = createYjsBackend(doc, "shared");
createSyncEngine(backend, adapter).connect();
const undoManager = new Y.UndoManager(backend.map, {
  trackedOrigins: new Set([backend.origin]),
});
```
createYjsBackend(map, options) syncs a Y.Map you already have, such as one nested in another map or in a subdocument; a map that is not part of a document throws a TypeError. The new origin option sets the origin, which must be unique to the backend; it defaults to a private Symbol, as before.
6f2f2e1: Report a synced map that a peer replaced. Once a peer set a new map in place of a backend's nested map, or of a map holding it, the backend lost every write, its store never saw the peer's state, and nothing told the app. It now calls the new onRemoved option once, which logs the error with console.error by default, so the app can connect a new engine over the map that replaced it. createYjsBackend also throws a TypeError for a map already removed from its document.
aa7cbc1: Implement CrdtBackend.revision: it counts the document's transactions that changed something, and is undefined while one is open. The sync engine then applies a remote change another listener heard of first before writing a local change, instead of the write throwing Length exceeded! on items the peer had deleted. write now diffs against the previous it is given even inside another transaction, where it used to read the document; the engine checks the revision before passing previous. Use it with the @homeostate/core release that adds CrdtBackend.revision, since an older engine passes previous without that check.

Patch Changes

a80be3b: Build the backend with createCrdtBackend from @homeostate/core, so the default text policy, what a write diffs against and leaving its own writes out of subscribe are written once, in core. Options, extras such as the Yjs backend's map and origin, and behaviour are unchanged. Use it with the @homeostate/core release that adds createCrdtBackend.
ceca144: Leave copying objects that a peer's __proto__ entry gave a prototype to the sync engine, which now does it for every backend. read() may return such an object as the document holds it; the store still never receives one. The Yjs backend still leaves __proto__ entries of a Y.Map out of what it reads. Use it with the @homeostate/core release whose engine copies such objects.
55812ce: Implement the CrdtBackend whose read returns a JsonObject and whose write takes a JsonObjectInput, with no casts at the boundary. Use it with the @homeostate/core release that narrows CrdtBackend.read and write.
Updated dependencies [39809d7]
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Updated dependencies [074eadc]
Updated dependencies [7e7171a]
- @homeostate/core@0.4.0

0.2.0

Minor Changes

f77d8a6: Add document persistence, so a synced document survives reloads, offline starts, and every peer and the sync server losing it. createPersistence in @homeostate/core keeps a CRDT document in a PersistenceAdapter; createYjsPersistable, createLoroPersistable and createAutomergePersistable expose each backend's document to it; and the new @homeostate/persist-indexeddb and @homeostate/persist-local-storage packages store it in IndexedDB or Web Storage. createMemoryPersistenceAdapter in @homeostate/core/testing is an in-memory adapter for tests.
d8e9906: Store strings as plain values unless a text option marks them as collaborative text. Every backend stored every string as its text type and merged concurrent replacements character by character, so two peers setting a filter to "active" and "completed" at once converged to "compctiveeted"; ids and timestamps merged the same way. Concurrent writes of a string now keep one of the written values.

Mark prose that should keep merging with the backend's new text option, which receives each string's path from the synced root:
```
createYjsBackend(doc, "shared", {
  text: (path) => path[0] === "todos" && path[2] === "title",
});
```
Yjs and Loro store other strings as plain map and list values, and Automerge as ImmutableString. read() returns plain strings for both kinds. Documents written by earlier releases hold every string as text: they read as before, and each string is stored as the configured kind the next time it changes. Give every backend writing to a document the same policy.

Core adds getChanges(a, b, { text }), which replaces strings outside the policy with one UPDATE; without the option every string is still diffed character by character. It also exports the TextPolicy and DiffOptions types, and exports applyStringChanges again for backends that find text stored as a plain value.

Patch Changes

732c2c8: Replace a plain array or object that other code stored in the synced map on the next write that changes it. Writing over a plain array threw, leaving earlier changes of the write applied on Yjs, and changes to a plain object were dropped, so the store and the document disagreed.
456fbad: Write undefined and functions the way JSON.stringify does in every backend: object entries holding them are left out, and such array items, holes included, become null. Writing the same state again produces no update.
- Yjs threw halfway through a write on an undefined array item or a nested function, and the part already applied replicated to peers, sometimes deleting an existing item. undefined object values were stored as present keys.
- Loro threw halfway through a write on a nested function or a sparse array, leaving a partial subtree that replicated. It stored undefined as null, and resent every undefined array item on each write.
- Automerge threw on every write after the store held an undefined array item, so nothing synced from that store again, and stored nested functions as {}.
getChanges takes json: true to diff the new state by that rule, passing only the values its changes carry through toJsonValue, newly exported from @homeostate/core, so a write does not copy the whole state. Custom backends should set it on write(next).
314e268: Sync keys named after Object.prototype members, and stop peers from replacing object prototypes through a __proto__ key. getChanges and the sync engine compared keys with in, so keys such as constructor or toString counted as always present and their deletions never replicated; the Valtio adapter had the same fault. A __proto__ key is now never diffed and is left out of remote state at any depth. The Yjs and Loro backends' read() turned a peer's __proto__ entry into an object's prototype, so its properties, such as isAdmin, appeared on other users' state; it now returns plain objects.
008091c: Diff each write against the previous state the sync engine passes, instead of serialising the document and comparing every item, so a local change costs the change rather than the whole state. A toggle at 500 todos took 146 µs with Yjs, 1.13 ms with Loro and 298 µs with Automerge, and now takes 14 µs, 35 µs and 182 µs. The Yjs backend still reads its document when written inside another transaction, and the Loro backend while other code has uncommitted edits, since those changes are not reported yet.
Updated dependencies [732c2c8]
Updated dependencies [f901667]
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Updated dependencies [008091c]
- @homeostate/core@0.3.0

0.1.3

Patch Changes

33c7b14: Mark the package side-effect free, so bundlers can drop modules that are not imported.
fb76f77: Preserve complete Unicode code points when diffing and applying string edits. Deleting or replacing supplementary characters such as emoji no longer corrupts text, deletes adjacent characters, or throws in the supplied CRDT backends.

String Change offsets remain UTF-16 code units. A string deletion can now carry a numeric UTF-16 deletion length in its third tuple entry; undefined still means one unit. Custom backends consuming getChanges must honor this length in one operation rather than delete one code unit per step. Array and object deletion semantics are unchanged.
Updated dependencies [a643bbe]
Updated dependencies [0bbf653]
Updated dependencies [fb76f77]
- @homeostate/core@0.2.0

0.3.0

Minor Changes

Patch Changes

0.2.0

Minor Changes

Patch Changes

0.1.3

Patch Changes

0.1.2

Patch Changes

0.1.1

Patch Changes