chore(release): 3.0.0-rc1

Diff: 2.3.0...3.0.0-rc1

.gitignore

@@ -11,3 +11,4 @@ node_modules
 coverage
 .idea
 .nyc_output
+dist/

CHANGELOG.md

@@ -0,0 +1,81 @@
+# [3.0.0-rc1](https://github.com/socketio/socket.io/compare/2.3.0...3.0.0-rc1) (2020-10-13)
+
+
+### Features
+
+* add ES6 module export ([8b6b100](https://github.com/socketio/socket.io/commit/8b6b100c284ccce7d85e55659e3397f533916847))
+* do not reuse the Engine.IO id ([2875d2c](https://github.com/socketio/socket.io/commit/2875d2cfdfa463e64cb520099749f543bbc4eb15))
+* remove Server#set() method ([029f478](https://github.com/socketio/socket.io/commit/029f478992f59b1eb5226453db46363a570eea46))
+* remove Socket#rooms object ([1507b41](https://github.com/socketio/socket.io/commit/1507b416d584381554d1ed23c9aaf3b650540071))
+* remove the 'origins' option ([a8c0600](https://github.com/socketio/socket.io/commit/a8c06006098b512ba1b8b8df82777349db486f41))
+* remove the implicit connection to the default namespace ([3289f7e](https://github.com/socketio/socket.io/commit/3289f7ec376e9ec88c2f90e2735c8ca8d01c0e97))
+* throw upon reserved event names ([4bd5b23](https://github.com/socketio/socket.io/commit/4bd5b2339a66a5a675e20f689fff2e70ff12d236))
+
+
+### BREAKING CHANGES
+
+* the 'origins' option is removed
+
+Before:
+
+```js
+new Server(3000, {
+  origins: ["https://example.com"]
+});
+```
+
+The 'origins' option was used in the allowRequest method, in order to
+determine whether the request should pass or not. And the Engine.IO
+server would implicitly add the necessary Access-Control-Allow-xxx
+headers.
+
+After:
+
+```js
+new Server(3000, {
+  cors: {
+    origin: "https://example.com",
+    methods: ["GET", "POST"],
+    allowedHeaders: ["content-type"]
+  }
+});
+```
+
+The already existing 'allowRequest' option can be used for validation:
+
+```js
+new Server(3000, {
+  allowRequest: (req, callback) => {
+    callback(null, req.headers.referer.startsWith("https://example.com"));
+  }
+});
+```
+
+* Socket#rooms is now a Set instead of an object
+
+* Namespace#connected is now a Map instead of an object
+
+* there is no more implicit connection to the default namespace:
+
+```js
+// client-side
+const socket = io("/admin");
+
+// server-side
+io.on("connect", socket => {
+  // not triggered anymore
+})
+
+io.use((socket, next) => {
+  // not triggered anymore
+});
+
+io.of("/admin").use((socket, next) => {
+  // triggered
+});
+```
+
+* the Server#set() method was removed
+
+This method was kept for backward-compatibility with pre-1.0 versions.
+