PerformanceObserverEntryList.getEntriesByName()
This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.
The getEntriesByName()
method of the PerformanceObserverEntryList
interface returns a list of explicitly observed performance entry objects for a given name
and entry type
. The list's members are determined by the set of entry types specified in the call to the observe()
method. The list is available in the observer's callback function (as the first parameter in the callback).
This method is exposed to Window
and Worker
interfaces.
Syntax
entries = list.getEntriesByName(name, type);
Parameters
name
- A
DOMString
representing the name of the entry to retrieve. type
Optional- A
DOMString
representing the type of entry to retrieve such as "mark
". The valid entry types are listed inPerformanceEntry.entryType
.
Return value
A list of explicitly observed performance entry objects that have the specified name
and type
. If the type
argument is not specified, only the name
will be used to determine the entries to return. The items will be in chronological order based on the entries' startTime
. If no objects meet the specified criteria, an empty list is returned.
Example
function print_perf_entry(pe) { console.log("name: " + pe.name + "; entryType: " + pe.entryType + "; startTime: " + pe.startTime + "; duration: " + pe.duration); } // Create observer for all performance event types var observe_all = new PerformanceObserver(function(list, obs) { var perfEntries; // Print all entries perfEntries = list.getEntries(); for (var i=0; i < perfEntries.length; i++) { print_perf_entry(perfEntries[i]); } // Print entries named "Begin" with type "mark" perfEntries = list.getEntriesByName("Begin", "mark"); for (var i=0; i < perfEntries.length; i++) { print_perf_entry(perfEntries[i]); } // Print entries with type "mark" perfEntries = list.getEntriesByType("mark"); for (var i=0; i < perfEntries.length; i++) { print_perf_entry(perfEntries[i]); } }); // subscribe to all performance event types observe_all.observe({entryTypes: ['frame', 'mark', 'measure', 'navigation', 'resource', 'server']}); var observe_frame = new PerformanceObserver(function(list, obs) { var perfEntries = list.getEntries(); // Should only have 'frame' entries for (var i=0; i < perfEntries.length; i++) { print_perf_entry(perfEntries[i]); } }); // subscribe to only the 'frame' event observe_frame.observe({entryTypes: ['frame']});
Specifications
Specification | Status | Comment |
---|---|---|
Performance Timeline Time Level 2 The definition of 'getEntriesByName()' in that specification. |
Editor's Draft | Initial definition of getEntriesByName() method. |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|
getEntriesByName() |
52.0 | 49 (49)[1] | No support | 39 | No support |
Feature | Android | Android Webview | Firefox Mobile (Gecko) | Firefox OS | IE Phone | Opera Mobile | Safari Mobile | Chrome for Android |
---|---|---|---|---|---|---|---|---|
getEntriesByName() |
No support | No support | 49.0 (49)[1] | No support | No support | 39 | No support | 52.0 |
[1] Only activated in Nightly builds. Controlled by the dom.enable_performance_observer
preference.
License
© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-us/docs/web/api/performanceobserverentrylist/getentriesbyname