feat: add custom error type SseError

Author: MatthewWid

docs/api.md

@@ -4,12 +4,13 @@
 
 ### Exports
 
-* [Session](#session)
-* [createSession](#createsession%3A-(constructorparameters<typeof-session>)-%3D>-promise<session>)
-* [Channel](#channel)
-* [createChannel](#createchannel%3A-(...args%3A-constructorparameters<typeof-channel>)-%3D>-channel)
-* [EventBuffer](#eventbuffer)
-* [createEventBuffer](#createeventbuffer-args-constructorparameterstypeof-eventbuffer--eventbuffer)
+* [`Session`](#session)
+* [`createSession`](#createsession%3A-(constructorparameters<typeof-session>)-%3D>-promise<session>)
+* [`Channel`](#channel)
+* [`createChannel`](#createchannel%3A-(...args%3A-constructorparameters<typeof-channel>)-%3D>-channel)
+* [`EventBuffer`](#eventbuffer)
+* [`createEventBuffer`](#createeventbuffer-args-constructorparameterstypeof-eventbuffer--eventbuffer)
+* [`SseError`](#sseerror)
 
 ## Documentation
 
@@ -69,6 +70,8 @@ If no event name is given, the event name is set to `"message"`.
 
 If no event ID is given, the event ID (and thus the [`lastId` property](#session%23lastid%3A-string)) is set to a unique string generated using a [cryptographic pseudorandom number generator](https://nodejs.org/api/crypto.html#cryptorandomuuidoptions).
 
+If the session has disconnected, an [`SseError`](#sseerror) will be thrown.
+
 Emits the `push` event with the given data, event name and event ID in that order.
 
 #### `Session#stream`: `(stream: Readable[, options: object]) => Promise<boolean>`
@@ -321,3 +324,7 @@ Get a copy of the buffer contents.
 Creates and returns an instance of an [EventBuffer](#eventbuffer).
 
 Takes the [same arguments as the EventBuffer class constructor](#new-eventbufferoptions--).
+
+### `SseError`
+
+Represents an SSE-related error thrown from within Better SSE.

src/Channel.ts

@@ -1,6 +1,7 @@
+import {Session, DefaultSessionState} from "./Session";
 import {TypedEmitter, EventMap} from "./lib/TypedEmitter";
 import {generateId} from "./lib/generateId";
-import {Session, DefaultSessionState} from "./Session";
+import {SseError} from "./lib/SseError";
 
 interface BroadcastOptions<
 	SessionState extends Record<string, unknown> = DefaultSessionState
@@ -77,7 +78,7 @@ class Channel<
 		}
 
 		if (!session.isConnected) {
-			throw new Error("Cannot register a non-active session.");
+			throw new SseError("Cannot register a non-active session.");
 		}
 
 		session.once("disconnected", () => {

src/Session.ts

@@ -11,6 +11,7 @@ import {createPushFromStream} from "./lib/createPushFromStream";
 import {createPushFromIterable} from "./lib/createPushFromIterable";
 import {serialize, SerializerFunction} from "./lib/serialize";
 import {sanitize, SanitizerFunction} from "./lib/sanitize";
+import {SseError} from "./lib/SseError";
 
 interface SessionOptions
 	extends Pick<EventBufferOptions, "serializer" | "sanitizer"> {
@@ -353,7 +354,7 @@ class Session<
 		eventId = generateId()
 	): this => {
 		if (!this.isConnected) {
-			throw new Error("Cannot push data to a non-active session.");
+			throw new SseError("Cannot push data to a non-active session.");
 		}
 
 		this.buffer.push(data, eventName, eventId);

src/index.ts

@@ -9,3 +9,5 @@ export * from "./createEventBuffer";
 
 export type {StreamOptions} from "./lib/createPushFromStream";
 export type {IterateOptions} from "./lib/createPushFromIterable";
+
+export * from "./lib/SseError";

src/lib/SseError.ts

@@ -0,0 +1,8 @@
+class SseError extends Error {
+	constructor(message: string) {
+		super(message);
+		this.message = `better-sse: ${message}`;
+	}
+}
+
+export {SseError};