JSON-RPC 2.0 module
Usage
npm i -E @prelude/jsonrpc
import * as Jsonrpc from '@prelude/jsonrpc'
Server-side handling
handle() attaches to a WebSocket-like transport with send, on, and removeListener or off methods. It accepts string payloads, event objects with a data property, ArrayBuffer, and array-buffer views such as Node buffers.
const detach = Jsonrpc.handle(socket, {
async call(method, params) {
if (method === 'sum' && Array.isArray(params)) {
return params.reduce((total, value) => total + Number(value), 0)
}
throw new Jsonrpc.JsonRpcError(Jsonrpc.ErrorCode.methodNotFound)
},
async notification(method, params) {
// Notifications are dispatched but never receive a response.
}
})
The handler accepts omitted, positional, or named params and string, numeric, or null IDs. It emits standard Parse Error, Invalid Request, Method Not Found, Invalid Params, and Internal Error objects. Mixed batches and notification-only batches follow JSON-RPC 2.0 response rules.
processMessage() exposes the protocol layer without a transport, which is useful for HTTP endpoints and tests; processMessageText() returns the same response already serialised, so it can be written to the wire without a second JSON.stringify pass over handler results.
Correlated client
const client = new Jsonrpc.Client(socket, { timeout: 5_000 })
const result = await client.call<number>('sum', [ 1, 2, 3 ])
await client.notify('changed', { path: '/tmp/value' })
client.dispose()
The client allocates IDs, correlates success and error responses, rejects remote errors as RemoteError, and removes pending calls after response, timeout, abort, transport close/error, or send failure. Duplicate and unknown responses do not create pending state.
Public protocol types
The package exports explicit Request, Notification, SuccessResponse, ErrorResponse, ErrorObject, Response, Params, and Id types. Error objects use the standard { code, message, data? } shape; no transport-specific fields are added.
License
This package is dedicated to the public domain under CC0 1.0.