RTCPeerConnection: getStats() method

selector Optional

A MediaStreamTrack for which to gather statistics. If this is null (the default value), statistics will be gathered for the entire RTCPeerConnection.

In older code and documentation, you may see a callback-based version of this function. This has been deprecated and its use is strongly discouraged. You should update any existing code to use the Promise-based version of getStats() instead. The parameters for the older form of getStats() are described below, to aid in updating existing code.

successCallback Deprecated

A callback function called once the report has been successfully generated.

failureCallback Deprecated

A callback function called once the report has failed to be generated.

A Promise which resolves with an RTCStatsReport object providing connection statistics. The report's contents depend on the selector and other details of the connection.

This method does not throw exceptions; instead, it rejects the returned promise with one of the following errors:

InvalidAccessError DOMException

Thrown when there is no RTCRtpSender or RTCRtpReceiver whose track matches the specified selector, or selector matches more than one sender or receiver.

This example creates a periodic function using setInterval() that collects statistics for an RTCPeerConnection every second, generating an HTML-formatted report and inserting it into a specific element in the DOM.

setInterval(() => {
  myPeerConnection.getStats(null).then((stats) => {
    let statsOutput = "";

    stats.forEach((report) => {
      statsOutput +=
        `<h2>Report: ${report.type}</h2>\n<strong>ID:</strong> ${report.id}<br>\n` +
        `<strong>Timestamp:</strong> ${report.timestamp}<br>\n`;

      // Now the statistics for this report; we intentionally drop the ones we
      // sorted to the top above

      Object.keys(report).forEach((statName) => {
        if (
          statName !== "id" &&
          statName !== "timestamp" &&
          statName !== "type"
        ) {
          statsOutput += `<strong>${statName}:</strong> ${report[statName]}<br>\n`;
        }
      });
    });

    document.querySelector(".stats-box").innerHTML = statsOutput;
  });
}, 1000);

This works by calling getStats(), then, when the promise is resolved, iterates over the RTCStats objects on the returned RTCStatsReport. A section is created for each report with a header and all of the statistics below, with the type, ID, and timestamp handled specially to place them at the top of the list.

Once the HTML for the report is generated, it is injected into the element whose class is "stats-box" by setting its innerHTML property.