Before this change, `require("socket.io-client").Socket` would return
"undefined".
Note: having access to the Socket class allows users to modify its
prototype.
Related: https://github.com/socketio/socket.io/issues/3726
Before this commit, an event sent in the "connect" handler could be
sent before the events that were buffered while disconnected.
```js
socket.on("connect", () => {
socket.emit("bar");
});
socket.emit("foo"); // buffered while disconnected
```
In the example above, the "bar" event was sent first, which is not
correct.
Related: https://github.com/socketio/socket.io-client/issues/1458
When passing the same `options` argument for two distinct Socket
instances, a new Manager was created:
```js
const opts = {};
const socket1 = io("/foo", opts);
const socket2 = io("/bar", opts);
console.log(socket1.io === socket2.io); // false
```
This bug was introduced by [1].
Note: the `options` argument is modified at the `socket.io-client`
level (path, query) and at the `engine.io-client` level (host, port),
which may not be optimal.
[1]: 7a0c2b504f
Related: https://github.com/socketio/socket.io/issues/3898
With autoUnref set to true (default: false), the Socket.IO client will
allow the program to exit if there is no other active timer/socket in
the event system.
```js
const socket = io({
autoUnref: true
});
```
Note: this option only applies to Node.js clients.
Related: https://github.com/socketio/socket.io-client/issues/1446
Previously, the following code:
```js
const socket1 = io({
path: "/test1"
});
const socket2 = io({
path: "/test2"
});
```
would result in one single Manager, with the "/test2" path being
silently ignored.
Two distinct Manager instances will now be created.
Related: https://github.com/socketio/socket.io-client/issues/1225
Having type `Object` it was not possible to set values, e.g.:
```ts
if (!this.socket.io.opts.query) {
this.socket.io.opts.query = {};
}
this.socket.io.opts.query.token = 'abc123';
```
Results in error:
> Element implicitly has an 'any' type because expression of type '"token"' can't be used to index type 'Object'.
When a given socket was disconnected, either by the server-side or by the client-side, the manager was closed too, regardless of the other connected sockets.
```js
const socket1 = io({
autoConnect: false
});
const socket2 = io("/test");
socket1.disconnect(); // also disconnect socket2
```
This bug was introduced in [1].
[1]: b60e909039
- rename "connect_error" to "error"
- remove "reconnecting" (duplicate of "reconnect_attempt")
The updated list of events emitted by the Manager:
- open: successful (re)connection
- error: (re)connection failure (previously: "connect_error") or error after a successful connection
- close: disconnection
- ping: ping packet
- packet: data packet
- reconnect_attempt: reconnection attempt (previously: "reconnect_attempt" & "reconnecting")
- reconnect: successful reconnection
- reconnect_error: reconnection failure
- reconnect_failed: reconnection failure after all attempts
For reference, the Socket instance emits the following events:
- connect: successful connection to a Namespace
- connect_error: connection failure
- disconnect: disconnection
The meaning is not modified: this packet type is still used by the
server when the connection to a namespace is refused.
Breaking change: the Socket instance will now emit a "connect_error"
event instead of "error" (which is not a reserved event anymore)
```js
// before
socket.on("error", () => {});
// after
socket.on("connect_error", () => {});
```
Inspired from EventEmitter2 [1]
The API is similar to the one on the server-side:
```js
socket.onAny((event, ...args) => {});
socket.prependAny((event, ...args) => {});
socket.offAny(); // remove all listeners
socket.offAny(listener);
const listeners = socket.listenersAny();
```
[1]: https://github.com/EventEmitter2/EventEmitter2
A volatile packet will be dropped if:
- the socket is not connected
- the low-level transport is not ready (for example, a HTTP POST request is already pending)
Syntax:
```js
socket.volatile.emit("volatile event", "might or might not be sent");
```
This event was added in 41956806a7
But it does not convey the information that the Socket is actually
sending a CONNECT packet to the server. It should maybe be moved to the
Socket#onopen() method, but let's remove it for now as it is not
documented anywhere.
These events cannot be used by the end users, because they are part of
the Socket.IO public API, so using them will now throw an error
explicitly.
Related: f7ed81e5d2
Previously, most of the events emitted by the Manager were also emitted
by the Socket instances, but it was somehow misleading for the end
users because they don't have the same meaning:
- Manager: the state of the low-level connection (with connection and reconnection events)
- Socket: the state of the connection to the Namespace (only 'connect', 'disconnect' and 'error')
For example, the `reconnect` event:
```js
socket.on("reconnect", () => {
console.log(socket.connected); // might be false, which is a bit surprising
});
```
Breaking change: the Socket instance will no longer forward the events
of its Manager
Those events can still be accessed on the Manager instance though:
```js
socket.io.on("reconnect", () => {
// ...
});
```
So that the call to the `has-binary` method can be skipped. Usage:
```
// with binary data
socket.binary(true).emit("binary", obj);
// without binary data
socket.binary(false).emit("string", obj);
// call to hasBin
socket.emit("guess", obj);
```
