TaskPriorityChangeEvent: previousPriority property
The readonly previousPriority
property of the TaskPriorityChangeEvent
interface returns the priority of the corresponding TaskSignal
before it was changed and this prioritychange
event was emitted.
This is the value that was set in the TaskPriorityChangeEvent
constructor argument options.previous
.
The new priority of the task can be read from event.target.priority
.
Value
A string, indicating the associated task's priority before it was changed.
This will be one of: "user-blocking"
, "user-visible"
, "background"
.
Examples
The code below shows the previousPriority
being obtained in a handler for a prioritychange
event.
js
// Listen for 'prioritychange' events on the controller's signal.
controller.signal.addEventListener("prioritychange", (event) => {
const previousPriority = event.previousPriority;
const newPriority = event.target.priority;
console.log(
`The priority changed from ${previousPriority} to ${newPriority}.`
);
});
A more complete live example can be found in prioritychange
event > Examples.
Specifications
Specification |
---|
Prioritized Task Scheduling # dom-taskprioritychangeevent-previouspriority |
Browser compatibility
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