LGTM1
On Monday, May 18, 2026 at 5:39:00 AM UTC-7 Shweta Bindal wrote:
Hi @Vincent <mailto:[email protected]>
This feature was shipped in 2019 by Safari.
203168 – [Clipboard API] Implement ClipboardItem.getType() for
platform clipboard items
<https://bugs.webkit.org/show_bug.cgi?id=203168> - this is the
bug under which it was shipped.
Regards,
Shweta Bindal
------------------------------------------------------------------------
*From:* Vincent Scheib <[email protected]>
*Sent:* Saturday, May 16, 2026 4:16 AM
*To:* Shweta Bindal <[email protected]>
*Cc:* blink-dev <[email protected]>; Rakesh Goulikar
<[email protected]>; Rohan Raja
<[email protected]>; ASHISH KUMAR <[email protected]>
*Subject:* [EXTERNAL] Re: [blink-dev] Intent to Ship: Selective
Clipboard Format Read
You don't often get email from [email protected]. Learn why
this is important <https://aka.ms/LearnAboutSenderIdentification>
Looking forward to this, it seems a good optimization no web
developer API change. How long has this been shipped in Safari?
On Thu, May 14, 2026 at 1:03 AM 'Shweta Bindal' via blink-dev
<[email protected]> wrote:
*Contact emails*
[email protected], [email protected]
<mailto:[email protected]>, [email protected]
<mailto:[email protected]>
*Explainer*
https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/ClipboardAPI/SelectiveClipboardFormatRead/explainer.md
<https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/ClipboardAPI/SelectiveClipboardFormatRead/explainer.md>
*Specification*
https://github.com/w3c/clipboard-apis/pull/248
<https://github.com/w3c/clipboard-apis/pull/248>
*Summary*
Enhances the Asynchronous Clipboard API by deferring actual
clipboard data retrieval from the OS until the web
application calls getType(). Instead of eagerly fetching all
available formats at read() time, the browser now returns
ClipboardItem objects with available MIME types but without
the underlying data, and reads from the OS clipboard only
when getType() is invoked. const items = await
navigator.clipboard.read(); // No data read yet const text =
await items.getType('text/plain'); // Only 'text/plain' data
read here This reduces CPU usage, improves the perceived
responsiveness of the API call, and optimizes the browser's
power consumption.
*Blink component*
Blink>DataTransfer
<https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3EDataTransfer%22>
*Web Feature ID*
async-clipboard <https://webstatus.dev/features/async-clipboard>
*Motivation*
Currently, web applications can read clipboard content
through the Async Clipboard API. However, the current
implementation eagerly fetches all MIME types from the OS
clipboard at read() time, regardless of which formats the
application actually needs. This feature defers the actual
data retrieval to getType() time, so the browser reads only
the requested MIME types from the OS clipboard when they are
needed, improving performance and reducing unnecessary data
transfer.
*Initial public proposal*
https://github.com/WICG/proposals/issues/224
<https://github.com/WICG/proposals/issues/224>
*TAG review*
None requested because this behavior has achieved consensus
in the Editing working group and matches what Safari already does
*TAG review status*
Not applicable
*Goals for experimentation*
NA
*Risks*
*Interoperability and Compatibility*
/No information provided/
/Gecko/:
Positive (https://github.com/mozilla/standards-positions/issues/1279
<https://github.com/mozilla/standards-positions/issues/1279>)
/WebKit/:
Shipped/Shipping
(https://github.com/WebKit/standards-positions/issues/537
<https://github.com/WebKit/standards-positions/issues/537>)
/Web developers/:
Positive (https://github.com/WICG/proposals/issues/224
<https://github.com/WICG/proposals/issues/224>) Webkit has
already implemented this behavior
/Other signals/:
*WebView application risks*
/Does this intent deprecate or change behavior of existing
APIs, such that it has potentially high risk for Android
WebView-based applications?/
No risks for WebView
*Debuggability*
No DevTools debugging support needed for this.
*Will this feature be supported on all six Blink platforms
(Windows, Mac, Linux, ChromeOS, Android, and Android WebView)?*
Yes
It is supported on all platforms because it is purely a
browser-internal optimization that changes when existing OS
clipboard APIs are called (deferring from read() time to
getType() time), without requiring any new platform-specific
clipboard capabilities or OS-level API changes.
*Is this feature fully tested by **web-platform-tests*
<https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md>*?*
No
Added initial tests to WPT, but further coverage is currently
blocked by missing test infrastructure. Created an issue for
that (https://issues.chromium.org/issues/508091414
<https://issues.chromium.org/issues/508091414>)
*Flag name on about://flags*
DeferOsClipboardReadCallToGetType
*Finch feature name*
/No information provided/
*Non-finch justification*
As previously collected in UseCounters 5684 and 5685,
telemetry tracking how often the clipboard changes between
read and getType (or consecutive getType calls) shows an
extremely low usage percentage (~0.0004). This data
demonstrates that the risk of breaking existing workflows is
negligible. Consequently, a Finch rollout is unnecessary.
*Rollout plan*
Will ship enabled for all users
*Requires code in //chrome?*
False
*Tracking bug*
https://issues.chromium.org/issues/435051711
<https://issues.chromium.org/issues/435051711>
*Estimated milestones*
Shipping on desktop
149
Shipping on Android
149
Shipping on WebView
149
Shipping on iOS
149
*Anticipated spec changes*
/Open questions about a feature may be a source of future web
compat or interop issues. Please list open issues (e.g. links
to known github issues in the project for the feature
specification) whose resolution may introduce web
compat/interop risk (e.g., changing to naming or structure of
the API in a non-backward-compatible way)./
N/A
*Link to entry on the Chrome Platform Status*
https://chromestatus.com/feature/5203433409871872?gate=6255790323269632
<https://chromestatus.com/feature/5203433409871872?gate=6255790323269632>
This intent message was generated by Chrome Platform Status
<https://chromestatus.com/>.
--
You received this message because you are subscribed to the
Google Groups "blink-dev" group.
To unsubscribe from this group and stop receiving emails from
it, send an email to [email protected]
<mailto:[email protected]>.
To view this discussion visit
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/JH0P153MB1062E1AE43E6CECD8926ED17D1072%40JH0P153MB1062.APCP153.PROD.OUTLOOK.COM
<https://groups.google.com/a/chromium.org/d/msgid/blink-dev/JH0P153MB1062E1AE43E6CECD8926ED17D1072%40JH0P153MB1062.APCP153.PROD.OUTLOOK.COM?utm_medium=email&utm_source=footer>.
--
You received this message because you are subscribed to the Google
Groups "blink-dev" group.
To unsubscribe from this group and stop receiving emails from it,
send an email to [email protected].
To view this discussion visit
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/4162c19e-98f8-4a20-9cc5-3f7db56bffa9n%40chromium.org
<https://groups.google.com/a/chromium.org/d/msgid/blink-dev/4162c19e-98f8-4a20-9cc5-3f7db56bffa9n%40chromium.org?utm_medium=email&utm_source=footer>.
