nw.js: URL.createObjectURL fails on 0.76.1

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Successfully reproduced against the latest version of NW.js?

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Current/Missing Behavior

URL.createObjectURL(new Blob([])) is the minimal code needed to reproduce the issue. In 0.76.1 the following error message is produced, regardless of input.

Uncaught TypeError: Failed to execute 'createObjectURL' on 'URL': Overload resolution failed.

Expected/Proposed Behavior

The expected behavior is that a URL to the blob is returned, such as:

blob:chrome-extension://hjnamambhlpahhgnmkmdplebghbjncpm/b1957c09-3e5c-48d3-b545-8052ddb77d3c

This works as expected on 0.75.0.

Additional Info

Operating System: Windows
NW.js Version: 0.76.1
Repro Link:
Code snippet: URL.createObjectURL(new Blob([]))
Crash report:

About this issue

Original URL
State: closed
Created a year ago
Comments: 18 (4 by maintainers)

Most upvoted comments

Please test this build: https://dl.nwjs.io/live-build/nw85/20240305-222312/9b99df3ea/v0.85.1/

rogerwang on Mar 6, 2024

I think I found a minimal repro for this: nwjs-issue8075.zip

It’s true that URL.createObjectURL(blob) fails in a worker only in recent versions of NW.js, but only when specifying "chromium-args": "--enable-node-worker" in package.json, which some frameworks (like ours) do.

In this case, in the context of the worker, the Blob constructor actually appears to be a version from Node.js (apparently from node:internal/blob) that overrides the browser one. Therefore since it’s not a real Blob that the browser understands, methods like URL.createObjectURL fail, but also checks like instanceof Blob also fail.

Hopefully this is enough information to be able to fix the issue now - we’re seeing reports of this from time to time (e.g. here).

AshleyScirra on Sep 27, 2023

@rogerwang - is an official NW.js 0.85.1 release coming up for this? Apparently the issue is affecting some Construct games, and it would be useful to know if a release is scheduled, or if we ought to be using a one-off build (which I’m a bit reluctant about as normally nightly releases are not as reliable)

AshleyScirra on Mar 7, 2024

From my testing, this is only broken inside workers, not on the main thread

Worker disabled: https://drive.google.com/file/d/1KO2yJpoG3yo7fXO0i64iWeTAwpZG_5-A/view?usp=drive_link
Worker enabled: https://drive.google.com/file/d/1_k4_dQT8B1XWPcjUNGnqAAdNGaMxV330/view?usp=drive_link

(Sorry, file too big for Github)

The bug still happens in 0.77.0

skymen on Jun 12, 2023