PerformanceEntry.toJSON()

The toJSON() method is a serializer; it returns a JSON representation of the performance entry object.

Note: This feature is available in Web Workers.

Syntax

json = perfEntry.toJSON();

Arguments

None
 

Return value

json
A JSON object that is the serialization of the PerformanceEntry object.

Example

The following example shows the use of the toJSON() method.

function run_PerformanceEntry() {
  log("PerformanceEntry support ...");

  if (performance.mark === undefined) {
    log("... performance.mark Not supported");
    return;
  }

  // Create some performance entries via the mark() method
  performance.mark("Begin");
  do_work(50000);
  performance.mark("End");

  // Use getEntries() to iterate through the each entry
  var p = performance.getEntries();
  for (var i=0; i < p.length; i++) {
    log("Entry[" + i + "]");
    check_PerformanceEntry(p[i]);
  }
}
function check_PerformanceEntry(obj) {
  var properties = ["name", "entryType", "startTime", "duration"];
  var methods = ["toJSON"];

  for (var i=0; i < properties.length; i++) {
    // check each property
    var supported = properties[i] in obj;
    if (supported)
      log("..." + properties[i] + " = " + obj[properties[i]]);
    else 
      log("..." + properties[i] + " = Not supported");
  }
  for (var i=0; i < methods.length; i++) {
    // check each method
    var supported = typeof obj[methods[i]] == "function";
    if (supported) {
      var js = obj[methods[i]]();
      log("..." + methods[i] + "() = " + JSON.stringify(js));
    } else {
      log("..." + methods[i] + " = Not supported");
    }
  }
}

Specifications

Specification Status Comment
Performance Timeline Level 2
The definition of 'toJSON' in that specification.
Candidate Recommendation Initial definition of toJSON() method.

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
toJSONChrome Full support YesEdge Full support 16Firefox Full support YesIE No support NoOpera Full support YesSafari Full support 11WebView Android Full support YesChrome Android Full support YesFirefox Android Full support 25Opera Android Full support YesSafari iOS Full support 11Samsung Internet Android Full support Yes

Legend

Full support  
Full support
No support  
No support

Document Tags and Contributors

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