ReportingObserver

Constructor

ReportingObserver()

Creates a new ReportingObserver object instance, which can be used to collect and access reports.

Instance properties

This interface has no properties defined on it.

Instance methods

ReportingObserver.disconnect()

Stops a reporting observer that had previously started observing from collecting reports.

ReportingObserver.observe()

Instructs a reporting observer to start collecting reports in its report queue.

ReportingObserver.takeRecords()

Returns the current list of reports contained in the observer's report queue, and empties the queue.

Events

This interface has no events that fire on it.

Examples

Displaying deprecation reports

This example shows how to observe "deprecation" reports using a ReportingObserver.

<pre id="log"></pre>

#log {
  height: 200px;
  margin: 10px;
  overflow: scroll;
  padding: 0.5rem;
  border: 1px solid black;
}

const logElement = document.querySelector("#log");
function log(text) {
  logElement.innerText = `${logElement.innerText}${text}\n`;
  logElement.scrollTop = logElement.scrollHeight;
}

JavaScript

First we construct a new ReportingObserver object to listen for reports with the type "deprecation", passing a callback that will receive and log the reports.

const options = {
  types: ["deprecation"],
  buffered: true,
};

const observer = new ReportingObserver((reports, observer) => {
  reports.forEach((report) => {
    // console.log(report);
    log(JSON.stringify(report, null, 2));
  });
}, options);

// Start the observer
observer.observe();

We then call the following code which uses synchronous XHR (deprecated API). Note that this is defined after the observer it triggers once the observer is running.

const xhr = new XMLHttpRequest();
xhr.open("GET", "/", false); // false = synchronous (deprecated)
xhr.send();

Results

On browsers that support deprecation reports, a report should be displayed below. Note that the type is "deprecation".

Specifications

Browser compatibility

See also

• Reporting API