initial commit

.gitignore

@@ -0,0 +1,34 @@
+# dependencies (bun install)
+node_modules
+
+# output
+out
+dist
+*.tgz
+
+# code coverage
+coverage
+*.lcov
+
+# logs
+logs
+_.log
+report.[0-9]_.[0-9]_.[0-9]_.[0-9]_.json
+
+# dotenv environment variable files
+.env
+.env.development.local
+.env.test.local
+.env.production.local
+.env.local
+
+# caches
+.eslintcache
+.cache
+*.tsbuildinfo
+
+# IntelliJ based IDEs
+.idea
+
+# Finder (MacOS) folder config
+.DS_Store

README.md

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+# arca-signaling
+
+To install dependencies:
+
+```bash
+bun install
+```
+
+To run:
+
+```bash
+bun run index.ts
+```
+
+This project was created using `bun init` in bun v1.2.12. [Bun](https://bun.sh) is a fast all-in-one JavaScript runtime.

bun.lock

@@ -0,0 +1,36 @@
+{
+  "lockfileVersion": 1,
+  "workspaces": {
+    "": {
+      "name": "arca-signaling",
+      "dependencies": {
+        "ulid": "^3.0.0",
+        "ws": "^8.18.2",
+      },
+      "devDependencies": {
+        "@types/bun": "latest",
+        "@types/ws": "^8.18.1",
+      },
+      "peerDependencies": {
+        "typescript": "^5",
+      },
+    },
+  },
+  "packages": {
+    "@types/bun": ["@types/bun@1.2.12", "", { "dependencies": { "bun-types": "1.2.12" } }, "sha512-lY/GQTXDGsolT/TiH72p1tuyUORuRrdV7VwOTOjDOt8uTBJQOJc5zz3ufwwDl0VBaoxotSk4LdP0hhjLJ6ypIQ=="],
+
+    "@types/node": ["@types/node@22.15.17", "", { "dependencies": { "undici-types": "~6.21.0" } }, "sha512-wIX2aSZL5FE+MR0JlvF87BNVrtFWf6AE6rxSE9X7OwnVvoyCQjpzSRJ+M87se/4QCkCiebQAqrJ0y6fwIyi7nw=="],
+
+    "@types/ws": ["@types/ws@8.18.1", "", { "dependencies": { "@types/node": "*" } }, "sha512-ThVF6DCVhA8kUGy+aazFQ4kXQ7E1Ty7A3ypFOe0IcJV8O/M511G99AW24irKrW56Wt44yG9+ij8FaqoBGkuBXg=="],
+
+    "bun-types": ["bun-types@1.2.12", "", { "dependencies": { "@types/node": "*" } }, "sha512-tvWMx5vPqbRXgE8WUZI94iS1xAYs8bkqESR9cxBB1Wi+urvfTrF1uzuDgBHFAdO0+d2lmsbG3HmeKMvUyj6pWA=="],
+
+    "typescript": ["typescript@5.8.3", "", { "bin": { "tsc": "bin/tsc", "tsserver": "bin/tsserver" } }, "sha512-p1diW6TqL9L07nNxvRMM7hMMw4c5XOo/1ibL4aAIGmSAt9slTE1Xgw5KWuof2uTOvCg9BY7ZRi+GaF+7sfgPeQ=="],
+
+    "ulid": ["ulid@3.0.0", "", { "bin": { "ulid": "dist/cli.js" } }, "sha512-yvZYdXInnJve6LdlPIuYmURdS2NP41ZoF4QW7SXwbUKYt53+0eDAySO+rGSvM2O/ciuB/G+8N7GQrZ1mCJpuqw=="],
+
+    "undici-types": ["undici-types@6.21.0", "", {}, "sha512-iwDZqg0QAGrg9Rav5H4n0M64c3mkR59cJ6wQp+7C4nI0gsmExaedaYLNO44eT4AtBBwjbTiGPMlt2Md0T9H9JQ=="],
+
+    "ws": ["ws@8.18.2", "", { "peerDependencies": { "bufferutil": "^4.0.1", "utf-8-validate": ">=5.0.2" }, "optionalPeers": ["bufferutil", "utf-8-validate"] }, "sha512-DMricUmwGZUVr++AEAe2uiVM7UoO9MAVZMDu05UQOaUII0lp+zOzLLU4Xqh/JvTqklB1T4uELaaPBKyjE1r4fQ=="],
+  }
+}

index.ts

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+import { WebSocket, WebSocketServer } from 'ws';
+import { ulid } from 'ulid';
+
+const wss = new WebSocketServer({ port: 8080 });
+
+const rooms = new Map<string, Set<string>>();
+const sockets = new Map<string, WebSocket>();
+
+wss.on('connection', (ws) => {
+    let peerId = ulid();
+
+    const join = (room: string) => {
+        if (!rooms.has(room)) {
+            rooms.set(room, new Set([peerId]));
+        } else {
+            rooms.get(room)!.add(peerId);
+        }
+    };
+
+    const unjoinAll = () => {
+        rooms.entries().forEach(([room, peers]) => {
+            peers.delete(peerId);
+            if (!peers.size) rooms.delete(room);
+        });
+    };
+
+    ws.on('message', (message) => {
+        try {
+            const text = message.toString('utf8');
+            const data = JSON.parse(text);
+
+            if (data.type === 'self') {
+                ws.send(JSON.stringify({
+                    type: 'self',
+                    id: peerId.toString(),
+                }));
+
+                return;
+            }
+
+            if (data.type === 'join' && typeof data.room === 'string') {
+                unjoinAll();
+                join(data.room);
+
+                const peers = rooms.get(data.room) ?? [];
+                peers.forEach((peer) => {
+                    sockets.get(peer)!.send(JSON.stringify({
+                        type: 'peers',
+                        peers: peers,
+                    }));
+                });
+
+                return;
+            }
+
+            if (data.type === 'offer' && typeof data.peer === 'string' && typeof data.offer === 'object') {
+                const otherWS = sockets.get(data.peer);
+                if (!otherWS) return;
+
+                otherWS.send(JSON.stringify({
+                    type: 'offer',
+                    from: peerId,
+                    offer: data.offer,
+                }));
+
+                return;
+            }
+
+            if (data.type === 'accept' && typeof data.peer === 'string' && typeof data.counterOffer === 'object') {
+                const otherWS = sockets.get(data.peer);
+                if (!otherWS) return;
+
+                otherWS.send(JSON.stringify({
+                    type: 'accept',
+                    from: peerId,
+                    counterOffer: data.counterOffer,
+                }));
+
+                return;
+            }
+
+            throw 0;
+        } catch (e) {
+            ws.send(JSON.stringify({
+                type: 'error',
+                message: 'Bad Request',
+            }));
+        }
+    });
+
+    ws.on('close', () => {
+        unjoinAll();
+        sockets.delete(peerId);
+    });
+});

package.json

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+{
+  "name": "arca-signaling",
+  "module": "index.ts",
+  "type": "module",
+  "private": true,
+  "devDependencies": {
+    "@types/bun": "latest",
+    "@types/ws": "^8.18.1"
+  },
+  "peerDependencies": {
+    "typescript": "^5"
+  },
+  "dependencies": {
+    "ulid": "^3.0.0",
+    "ws": "^8.18.2"
+  }
+}

tsconfig.json

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+{
+  "compilerOptions": {
+    // Environment setup & latest features
+    "lib": ["ESNext"],
+    "target": "ESNext",
+    "module": "ESNext",
+    "moduleDetection": "force",
+    "jsx": "react-jsx",
+    "allowJs": true,
+
+    // Bundler mode
+    "moduleResolution": "bundler",
+    "allowImportingTsExtensions": true,
+    "verbatimModuleSyntax": true,
+    "noEmit": true,
+
+    // Best practices
+    "strict": true,
+    "skipLibCheck": true,
+    "noFallthroughCasesInSwitch": true,
+    "noUncheckedIndexedAccess": true,
+
+    // Some stricter flags (disabled by default)
+    "noUnusedLocals": false,
+    "noUnusedParameters": false,
+    "noPropertyAccessFromIndexSignature": false
+  }
+}