PerformanceObserverEntryList.getEntriesByName()
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).
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 |
---|
Performance Timeline # dom-performanceobserverentrylist-getentriesbyname |
Browser compatibility
BCD tables only load in the browser