BackgroundFetchRegistration: progress event
The progress
event of the BackgroundFetchRegistration
interface thrown when the associated background fetch progresses.
Practically, this event is fired when any of the following properties will return a new value:
uploaded
,downloaded
,result
, orfailureReason
.
Syntax
Use the event name in methods like addEventListener()
, or set the onprogress
event property on the relevant BackgroundFetchRegistration
object.
addEventListener('progress', event => { })
onprogress = event => { }
Event type
A generic Event
with no added properties.
Example
The following example demonstrates how to log the progress of a download. The code first checks that a downloadTotal
was provided when the background fetch was registered. This is then used to calculate the percentage, based on the downloaded
property.
bgFetch.addEventListener('progress', () => {
if (!bgFetch.downloadTotal) return;
const percent = Math.round(bgFetch.downloaded / bgFetch.downloadTotal * 100);
console.log(`Download progress: ${percent}%`);
});
Specifications
Specification |
---|
Background Fetch # background-fetch-registration-events |
Browser compatibility
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