downloads.onChanged
The onChanged()
event of the downloads
API is fired when any of a downloads.DownloadItem
's properties changes (except for bytesReceived
).
The listener is passed a downloadDelta
as a parameter — an object containing the downloadId
of the downloads.DownloadItem
object in question, plus the status of all the properties that changed.
Syntax
js
browser.downloads.onChanged.addListener(listener)
browser.downloads.onChanged.removeListener(listener)
browser.downloads.onChanged.hasListener(listener)
Events have three functions:
addListener(listener)
-
Adds a listener to this event.
removeListener(listener)
-
Stop listening to this event. The
listener
argument is the listener to remove. hasListener(listener)
-
Check whether a given
listener
is registered for this event. Returnstrue
if it is listening,false
otherwise.
addListener syntax
Parameters
listener
-
The function called when this event occurs. This function will be passed this argument:
downloadDelta
-
An
object
representing thedownloads.DownloadItem
object that changed, and the status of all the properties that changed in it. See the downloadDelta section for more details.
Additional objects
downloadDelta
The downloadDelta
object has the following properties available:
id
-
An
integer
representing theid
of thedownloads.DownloadItem
that changed. url
Optional-
A
downloads.StringDelta
object describing a change in adownloads.DownloadItem
'surl
. filename
Optional-
A
downloads.StringDelta
object describing a change in adownloads.DownloadItem
'sfilename
. danger
Optional-
A
downloads.StringDelta
object describing a change in adownloads.DownloadItem
'sdanger
. mime
Optional-
A
downloads.StringDelta
object describing a change in adownloads.DownloadItem
'smime
. startTime
Optional-
A
downloads.StringDelta
object describing a change in adownloads.DownloadItem
'sstartTime
. endTime
Optional-
A
downloads.StringDelta
object describing a change in adownloads.DownloadItem
'sendTime
. state
Optional-
A
downloads.StringDelta
object describing a change in adownloads.DownloadItem
'sstate
. canResume
Optional-
A
downloads.BooleanDelta
object describing a change in adownloads.DownloadItem
'scanResume
status. paused
Optional-
A
downloads.BooleanDelta
object describing a change in adownloads.DownloadItem
'spaused
status. error
Optional-
A
downloads.StringDelta
object describing a change in adownloads.DownloadItem
'serror
status. totalBytes
Optional-
A
downloads.DoubleDelta
object describing a change in adownloads.DownloadItem
'stotalBytes
. fileSize
Optional-
A
downloads.DoubleDelta
object describing a change in adownloads.DownloadItem
'sfileSize
. exists
Optional-
A
downloads.BooleanDelta
object describing a change in adownloads.DownloadItem
'sexists
status.
Browser compatibility
BCD tables only load in the browser
Examples
Log a message when downloads complete:
js
function handleChanged(delta) {
if (delta.state && delta.state.current === "complete") {
console.log(`Download ${delta.id} has completed.`);
}
}
browser.downloads.onChanged.addListener(handleChanged);
Note: This API is based on Chromium's chrome.downloads
API.