accordsync library

Classes

AccordClient: An Accord device. Writes apply locally at once and are saved to storage; sync pushes them and pulls everyone else's, in the background or on demand. Port of @accordsync/client.
AddOp: Adds an element to a set; the op id is its tag. deps lists the element's tags the writer could see: the add replaces them, while a concurrent remove still loses.
AssignOp: Writes a value. For lww the highest clock wins; for conflict, deps lists the values the writer could see, and the assign supersedes exactly those (ADR-0003).
ConflictInfo: A conflict() field holding more than one value. Equal when the record, field and values are.
ConflictState
CounterState
ExitItem: The record left this device's read scope (ADR-0004).
FieldState: Per-field state. Each strategy's applyOp is commutative and associative over distinct ops: any delivery order of the same ops gives the same state. The replica applies each op at most once, which makes the merge idempotent. Port of strategies.ts.
Hlc: Hybrid logical clock: physical time + logical counter + node id.
HttpTransport: Talks to an Accord server over HTTPS (see the server's docs/protocol.md).
IncOp: Adds by (a positive or negative integer) to a counter.
LocalWriter: One device's replica plus the means to write to it: every local write becomes an op, applied locally first and returned so the caller can queue it for sync. Port of writer.ts.
LwwState
MemoryStorage: In-memory storage: for tests, and for apps that accept losing unsynced writes on restart.
Op: One change to one field of one record. Port of op.ts.
OpItem: An op, in the wire format.
PullItem: One item of a pull page.
PullPage
PullResult
PushResult: The server's answer to a push.
RecordSnapshot: A record's state with its history folded away (log compaction, ADR-0008).
RemoveOp: Removes the add tags in deps (the ones the writer had seen); concurrent adds survive.
Replica: An op log and the state projected from it. Pure: no I/O, no clock. Two replicas holding the same set of ops always read the same state, whatever order the ops arrived in. Port of replica.ts.
ResyncRequired: The server asks the device to drop its data and pull from zero.
SetState
SnapshotItem: A compacted record (ADR-0008).
StorageAdapter: Durable storage for a device. commit must be atomic: after a crash, either all of a transaction is visible or none of it.
StorageSnapshot: Everything a device has stored.
StorageTx: One atomic change. Applied in this order: clear, delete, put, outbox changes, meta.
StoredMeta: What a device must remember between launches.
Transport: How a client reaches the server. HttpTransport is the real one; tests can fake it.

Enums

ApplyResult
Strategy: How a field merges concurrent writes. Port of schema.ts.

Constants

absent → const Object: Marks a field with no value (never written): left out of reads and snapshots, like JavaScript's undefined. A field written with null reads as null.
defaultMaxSkewMs → const int
kinds → const Map<Strategy, List<String>>: The op kinds each strategy accepts.
maxCounter → const int: The largest counter value; one more rolls the clock into the next millisecond.
maxSafeInteger → const int: The largest integer JavaScript represents exactly: clocks and counts stay within it.
protocolVersion → const int: Version of the sync protocol spoken between Accord clients and servers.

Functions

applyOp(FieldState state, Op op) → void: Applies op to state in place. The op must already be validated against the schema.
assertNode(String node) → void: Throws unless node is a valid node (device) id: [A-Za-z0-9_-]{1,64}.
canonicalJson(Object? value) → String: JSON with object keys in a canonical order, so equal values always serialise to the same string.
compareElements(Object a, Object b) → int: Numbers first (ascending), then strings (by UTF-16 code unit), as in the TypeScript core.
compareOpIds(OpId a, OpId b) → int: Sort order for op ids: UTF-16 code units, exactly like JavaScript's < on strings.
conflict() → Strategy
counter() → Strategy
decodeOp(Object? input) → Op: Parses untrusted input into an op, or throws with the reason. Schema checks happen later.
defineSchema(Schema schema) → Schema: Checks and returns a schema.
emptyState(Strategy strategy) → FieldState
encodeOp(Op op) → Map<String, Object?>: An op as it travels over the network and sits in golden vectors. Port of wire.ts.
fieldObservedDeps(FieldState state, [Object? element]) → List<OpId>: Op ids a writer must cite in deps: live conflict values, or the tags of a set element.
fieldsOf(Schema schema, String record) → Map<String, Strategy>
jsKeyOrder(Iterable<String> keys) → List<String>: The order JavaScript gives the keys of an object built from code-unit-sorted entries.
jsNumber(num n) → String: A number as JSON.stringify prints it.
lww() → Strategy: lww(), counter(), set(), conflict(): the same declarations as the TypeScript schema.
parseOpId(String opId) → ({String device, int seq}): The device and sequence number of an op id.
randomDeviceId([Random? random]) → String: A random device id from a secure source (Random.secure). Device ids must never collide, and are never derived from the hardware.
readState(FieldState state) → Object?: A field as the app sees it: a JSON value, a sorted list (set), an int (counter), or for a conflict() field {'value': v} / {'conflicted': [{'value': v, 'opId': id}, …]}. absent when never written.
recordType(String record) → String: The type of a record id (dossier for dossier:91).
sameElement(Object? a, Object? b) → bool: Set elements compare like JavaScript's ===: 1 and 1.0 are the same element.
set() → Strategy
snapshotState(FieldState state) → Map<String, Object?>: A field's live state as JSON; tombstones are dropped (ADR-0008). Same shape as the TypeScript FieldSnapshot, so snapshots from the server load here unchanged.
stateFromSnapshot(Map<String, Object?> snap) → FieldState
strategyFor(Schema schema, String record, String field) → Strategy: The strategy for record.field, or an error naming what is wrong.

Typedefs

ConflictValue = ({OpId opId, Object? value}): One of the values a conflicted field holds, and the op that wrote it.
OpId = String: deviceId:sequence. Unique per op, so applying an op twice is a no-op.
Refusal = ({String field, OpId opId, String reason, String record}): A local write the server refused. It has already been rolled back on this device.
Schema = Map<String, Map<String, Strategy>>: Record type → field → strategy.
SyncStatus = ({int cursor, Object? lastError, int? lastSyncAt, int pending}): Where sync stands.

Exceptions / Errors

AccordException: An op, record or schema that Accord refuses, with the reason.
ClockSkewException: A remote clock too far ahead of this one: the op is refused instead of winning every merge.
HttpError

accordsync library

Classes

Enums

Constants

Functions

Typedefs

Exceptions / Errors

accordsync package

accordsync library