add precall test interface

JitsiMeetJS.ts

@@ -35,6 +35,7 @@ import * as E2ePingEvents from './service/e2eping/E2ePingEvents';
 import { createGetUserMediaEvent } from './service/statistics/AnalyticsEvents';
 import *  as RTCStatsEvents from './modules/RTCStats/RTCStatsEvents';
 import { VideoType } from './service/RTC/VideoType';
+import runPreCallTest, { IceServer, PreCallResult } from './modules/statistics/PreCallTest';
 
 const logger = Logger.getLogger(__filename);
 
@@ -477,6 +478,16 @@ export default {
         NetworkInfo.updateNetworkInfo({ isOnline });
     },
 
+    /**
+     * Run a pre-call test to check the network conditions.
+     * 
+     * @param {IceServer} iceServers  - The ICE servers to use for the test,
+     * @returns {Promise<PreCallResult | string>} - A Promise that resolves with the test results or rejects with an error message.
+     */
+    runPreCallTest(iceServers) {
+        return runPreCallTest(iceServers);
+    },
+
     /**
      * Represents a hub/namespace for utility functionality which may be of
      * interest to lib-jitsi-meet clients.

modules/statistics/PreCallTest.ts

@@ -0,0 +1,48 @@
+import PreCallTest from 'vo_precalltest/src/main.js';
+
+
+export interface PreCallResult {
+    throughput: number; // Maximum bandwidth reached in kbps  (kilo bits per second).
+    fractionalLoss: number; // Packet loss percentage over all the test traffic.
+    rtt: number;  // Round trip time in milliseconds.
+    jitter: number; 
+    mediaConnectivity: boolean; // Whether the data channel was able to send data or not.
+}
+
+// Same interface as a PeerConnection configuration object.
+export interface IceServer {
+    urls: Array<string> | string;
+    username?: string;
+    credential?: string;
+}
+
+let preCallTest: any = null
+
+/**
+ * Run a pre-call test to check the network conditions. It uses a TURN server to establish
+ * a connection between two PeerConnections using the server as a relay. Afterwards it sends 
+ * some test traffic through a data channel to measure the network conditions, these are 
+ * recorded and returned through a Promise.
+ * 
+ * @param {Array<IceServer>} - The ICE servers to use for the test, these are passes to the PeerConnection constructor. 
+ * @returns {Promise<PreCallResult | string>} - A Promise that resolves with the test results or rejects with an error message.
+ */
+export default async function runPreCallTest(iceServers: Array<IceServer>): Promise<PreCallResult | string> {
+    // On initialization, the PreCallTest object simply does some checks and some browsers verifications,
+    // these seem to be reusable, so we'll keep the object around.
+    preCallTest || (preCallTest = new PreCallTest())
+
+    return new Promise((resolve, reject) => {
+        // It's not explicitly stated in the code, but if message is not null, something went wrong,
+        // so we'll treat it as an error.
+        preCallTest.start(iceServers, (result, message) => {
+            if (message) {
+                reject(message);
+
+                return;
+            }
+
+            resolve(result);
+        });
+    });
+}