Performance extension type

The Performance interface provides access to performance-related information for the current page.

Performance entries are specific to each execution context. You can access performance information for code running in a window via Window.performance, and for code running in a worker via WorkerGlobalScope.performance.

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API documentation sourced from MDN Web Docs.

on

• JSObject

Implemented types

• EventTarget
• JSObject

Available extensions

• JSAnyOperatorExtension
• JSAnyUtilityExtension
• JSObjectUnsafeUtilExtension
• NullableUndefineableJSAnyExtension

Properties

eventCounts → EventCounts

The read-only performance.eventCounts property is an EventCounts map containing the number of events which have been dispatched per event type.

no setter

hashCode → int

The hash code for this object.

no setter, inherited

isDefinedAndNotNull → bool

Available on JSAny?, provided by the NullableUndefineableJSAnyExtension extension

no setter

isNull → bool

Available on JSAny?, provided by the NullableUndefineableJSAnyExtension extension

Whether this value corresponds to JavaScript null.

no setter

isTruthy → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of !!this in JavaScript.

no setter

isUndefined → bool

Available on JSAny?, provided by the NullableUndefineableJSAnyExtension extension

Whether this value corresponds to JavaScript undefined.

no setter

isUndefinedOrNull → bool

Available on JSAny?, provided by the NullableUndefineableJSAnyExtension extension

no setter

navigation → PerformanceNavigation

The legacy Performance.navigation read-only property returns a PerformanceNavigation object representing the type of navigation that occurs in the given browsing context, such as the number of redirections needed to fetch the resource.

no setter

not → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of !this in JavaScript.

no setter

onresourcetimingbufferfull ↔ EventHandler?

getter/setter pair

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

timeOrigin → double

The timeOrigin read-only property of the Performance interface returns the high resolution timestamp that is used as the baseline for performance-related timestamps.

no setter

timing → PerformanceTiming

The legacy Performance.timing read-only property returns a PerformanceTiming object containing latency-related performance information.

no setter

Methods

add(JSAny? any) → JSAny

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this + any in JavaScript.

addEventListener(String type, EventListener? callback, [JSAny options]) → void

The addEventListener() method of the EventTarget interface sets up a function that will be called whenever the specified event is delivered to the target.

inherited

and(JSAny? any) → JSAny?

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this && any in JavaScript.

callMethod<R extends JSAny?>(JSAny method, [JSAny? arg1, JSAny? arg2, JSAny? arg3, JSAny? arg4]) → R

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Calls method on this JSObject with up to four arguments.

callMethodVarArgs<R extends JSAny?>(JSAny method, [List<JSAny?>? arguments]) → R

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Calls method on this JSObject with a variable number of arguments.

clearMarks([String markName]) → void

The clearMarks() method removes all or specific PerformanceMark objects from the browser's performance timeline.

clearMeasures([String measureName]) → void

The clearMeasures() method removes all or specific PerformanceMeasure objects from the browser's performance timeline.

clearResourceTimings() → void

The clearResourceTimings() method removes all performance entries with an PerformanceEntry.entryType of "resource" from the browser's performance timeline and sets the size of the performance resource data buffer to zero.

dartify() → Object?

Available on JSAny?, provided by the JSAnyUtilityExtension extension

Converts a JavaScript value to the Dart equivalent if possible.

delete(JSAny property) → JSBoolean

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Deletes the property with key property from this JSObject.

dispatchEvent(Event event) → bool

The dispatchEvent() method of the EventTarget sends an Event to the object, (synchronously) invoking the affected event listeners in the appropriate order. The normal event processing rules (including the capturing and optional bubbling phase) also apply to events dispatched manually with dispatchEvent().

inherited

divide(JSAny? any) → JSAny

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this / any in JavaScript.

equals(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this == any in JavaScript.

exponentiate(JSAny? any) → JSAny

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this ** any in JavaScript.

getEntries() → PerformanceEntryList

The getEntries() method returns an array of all PerformanceEntry objects currently present in the performance timeline.

getEntriesByName(String name, [String type]) → PerformanceEntryList

The getEntriesByName() method returns an array of PerformanceEntry objects currently present in the performance timeline with the given name and type.

getEntriesByType(String type) → PerformanceEntryList

The getEntriesByType() method returns an array of PerformanceEntry objects currently present in the performance timeline for a given type.

getProperty<R extends JSAny?>(JSAny property) → R

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

The value of the property key property of this JSObject.

greaterThan(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this > any in JavaScript.

greaterThanOrEqualTo(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this >= any in JavaScript.

has(String property) → bool

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Shorthand helper for hasProperty to check whether this JSObject contains the property key property, but takes and returns a Dart value.

hasProperty(JSAny property) → JSBoolean

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Whether or not this JSObject contains the property key property.

instanceof(JSFunction constructor) → bool

Available on JSAny?, provided by the JSAnyUtilityExtension extension

Whether this JSAny? is an instanceof constructor.

instanceOfString(String constructorName) → bool

Available on JSAny?, provided by the JSAnyUtilityExtension extension

Whether this JSAny? is an instanceof the constructor that is defined by constructorName, which is looked up in the globalContext.

isA<T extends JSAny?>() → bool

Available on JSAny?, provided by the JSAnyUtilityExtension extension

Whether this JSAny? is an instance of the JavaScript type that is declared by T.

lessThan(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this < any in JavaScript.

lessThanOrEqualTo(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this <= any in JavaScript.

mark(String markName, [PerformanceMarkOptions markOptions]) → PerformanceMark

The mark() method creates a named PerformanceMark object representing a high resolution timestamp marker in the browser's performance timeline.

measure(String measureName, [JSAny startOrMeasureOptions, String endMark]) → PerformanceMeasure

The measure() method creates a named PerformanceMeasure object representing a time measurement between two marks in the browser's performance timeline.

modulo(JSAny? any) → JSAny

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this % any in JavaScript.

multiply(JSAny? any) → JSAny

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this * any in JavaScript.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

notEquals(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this != any in JavaScript.

now() → double

The performance.now() method returns a high resolution timestamp in milliseconds. It represents the time elapsed since Performance.timeOrigin (the time when navigation has started in window contexts, or the time when the worker is run in Worker and ServiceWorker contexts).

or(JSAny? any) → JSAny?

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this || any in JavaScript.

removeEventListener(String type, EventListener? callback, [JSAny options]) → void

The removeEventListener() method of the EventTarget interface removes an event listener previously registered with EventTarget.addEventListener from the target. The event listener to be removed is identified using a combination of the event type, the event listener function itself, and various optional options that may affect the matching process; see Matching event listeners for removal.

inherited

setProperty(JSAny property, JSAny? value) → void

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Write the value of property key property of this JSObject.

setResourceTimingBufferSize(int maxSize) → void

The setResourceTimingBufferSize() method sets the desired size of the browser's resource timing buffer which stores the "resource" performance entries.

strictEquals(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this === any in JavaScript.

strictNotEquals(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this !== any in JavaScript.

subtract(JSAny? any) → JSAny

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this - any in JavaScript.

toJSON() → JSObject

The toJSON() method of the Performance interface is a ; it returns a JSON representation of the Performance object.

toString() → String

A string representation of this object.

inherited

typeofEquals(String typeString) → bool

Available on JSAny?, provided by the JSAnyUtilityExtension extension

Whether the result of typeof on this JSAny? is typeString.

unsignedRightShift(JSAny? any) → JSNumber

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this >>> any in JavaScript.

Operators

operator ==(Object other) → bool

The equality operator.

inherited

operator [](String property) → JSAny?

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Shorthand helper for getProperty to get the value of the property key property of this JSObject, but takes and returns a Dart value.

operator []=(String property, JSAny? value) → void

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Shorthand helper for setProperty to write the value of the property key property of this JSObject, but takes a Dart value.