Report

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The Report interface of the Reporting API represents a single report.

Reports can be accessed in a number of ways:

  • Via the ReportingObserver.takeRecords() method — this returns all reports in an observer's report queue, and then empties the queue.
  • Via the reports parameter of the callback function passed into the ReportingObserver() constructor upon creation of a new observer instance. This contains the list of reports currently contained in the observer's report queue.
  • By sending requests to the endpoints defined via the Report-To HTTP header.

Properties

Report.body Experimental Read only

The body of the report, which is a ReportBody object containing the detailed report information.

Report.type Experimental Read only

The type of report generated, e.g. deprecation or intervention.

Report.url Experimental Read only

The URL of the document that generated the report.

Methods

This interface has no methods defined on it.

Events

This interface has no events that fire on it.

Examples

In our deprecation_report.html example, we create a simple reporting observer to observe usage of deprecated features on our web page:

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

const observer = new ReportingObserver((reports, observer) => {
  reportBtn.onclick = () => displayReports(reports);
}, options);

We then tell it to start observing reports using ReportingObserver.observe(); this tells the observer to start collecting reports in its report queue, and runs the callback function specified inside the constructor:

observer.observe();

Because of the event handler we set up inside the ReportingObserver() constructor, we can now click the button to display the report details.

image of a jolly bearded man with various stats displayed below it about a deprecated feature

The report details are displayed via the displayReports() function, which takes the observer callback's reports parameter as its parameter:

function displayReports(reports) {
  const outputElem = document.querySelector('.output');
  const list = document.createElement('ul');
  outputElem.appendChild(list);

  reports.forEach((report, i) => {
    let listItem = document.createElement('li');
    let textNode = document.createTextNode(`Report ${i + 1}, type: ${report.type}`);
    listItem.appendChild(textNode);
    let innerList = document.createElement('ul');
    listItem.appendChild(innerList);
    list.appendChild(listItem);

    for (const key in report.body) {
      const innerListItem = document.createElement('li');
      const keyValue = report.body[key];
      innerListItem.textContent = `${key}: ${keyValue}`;
      innerList.appendChild(innerListItem);
    }
  });
}

The reports parameter contains an array of all the reports in the observer's report queue. We loop over each report using a forEach() loop, then iterate over each entry of in the report's body using a for...in structure, displaying each key/value pair inside a list item.

Specifications

Specification
Reporting API
# dom-report

Browser compatibility

BCD tables only load in the browser

See also