@streamsy/json

Typed JSON protocol and stream wrappers for Streamsy durable streams.

JsonProtocol<T>/JsonStream<T> wrap a @streamsy/core StreamProtocolFactory so that stream messages are encoded and decoded as application/json values through a JsonCodec<T> or a Standard Schema validator.

Usage

import { createMemoryStorageAdapter, createStreamProtocol } from "@streamsy/core";
import { createJsonProtocol, type JsonCodec } from "@streamsy/json";

type User = { id: string; name: string };

const userCodec: JsonCodec<User> = {
  encode: (value) => value,
  decode: (value) => value as User,
};

const protocol = createStreamProtocol({
  storage: { adapter: createMemoryStorageAdapter() },
});
const json = createJsonProtocol(protocol, userCodec);

const created = await json.create("users", {
  initialMessage: { id: "u1", name: "Alice" },
});
if (created.status === "created") {
  await created.stream.append({ id: "u2", name: "Bob" });
  const read = await created.stream.read();
  if (read.status === "ok") {
    read.messages.map((message) => message.value.name); // ["Alice", "Bob"]
  }
}

Values that fail codec or schema validation reject at append with JsonValidationError; stored messages that fail to decode or validate on read surface as an invalid-json read status.

Exports

• createJsonProtocol, JsonProtocol, JsonStream
• JsonValidationError, normalizeJsonCodec, JSON_CONTENT_TYPE
• types: JsonCodec, JsonSchema, JsonStoredMessage, and the typed create/get/read/readLive result and option types

License

MIT