Vitest v4 + JSDOM: URL.createObjectUrl fails due to mismatching Blob constructors #8917
Description
Describe the bug
When using Vitest V4 (4.0.6) with JSDOM (both 26 and 27, that I checked), the following code throws:
/// @vitest-environment jsdom
import { describe, it, expect } from "vitest";
describe("createObjectUrl", () => {
it("constructs URL (if present)", async () => {
expect(() => {
if (URL.createObjectURL !== undefined) {
URL.createObjectURL(new Blob());
}
}).not.toThrow();
});
});FAIL blob-url-jsdom.spec.ts > createObjectUrl > constructs URL (if present)
AssertionError: expected [Function] to not throw an error but 'TypeError [ERR_INVALID_ARG_TYPE]: The…' was thrown
- Expected:
undefined
+ Received:
"TypeError [ERR_INVALID_ARG_TYPE]: The \"obj\" argument must be an instance of Blob. Received an instance of Blob"
❯ blob-url-jsdom.spec.ts:10:12
8| URL.createObjectURL(new Blob());
9| }
10| }).not.toThrow();
| ^
11| });
12| });In our repository, this code comes from a dependency, which checks for URL.createObjectURL and calls it conditionally. In v3, where URL.createObjectURL is not defined in a JSDOM environment, this is ok.
What I believe happens here, is that the Blob constructor is mismatching, between the node global (from node:buffer) and what JSDOM provides. I think ultimately it is the node URL.createObjectUrl that gets used, but with the JSDOM Blob.
For example, if I stub the global Blob to use the node Blob directly:
import { Blob as NodeBlob } from 'node:buffer';
vi.stubGlobal('Blob', NodeBlob);...tests seem to pass again.
Reproduction
In addition to the example above, I have a reproduction at https://github.com/fpapado/vitest-v4-jsdom-blob-and-create-object-url, with JSDOM, happy-dom and Node environments. Of the three, only JSDOM fails.
System Info
System:
OS: macOS 15.6.1
CPU: (10) arm64 Apple M1 Pro
Memory: 108.50 MB / 32.00 GB
Shell: 5.9 - /bin/zsh
Binaries:
Node: 24.11.0 - /Users/fotis/.local/state/fnm_multishells/42777_1762175329180/bin/node
npm: 11.6.1 - /Users/fotis/.local/state/fnm_multishells/42777_1762175329180/bin/npm
pnpm: 10.15.0 - /Users/fotis/.local/state/fnm_multishells/42777_1762175329180/bin/pnpm
Browsers:
Chrome: 141.0.7390.123
Chrome Canary: 144.0.7505.0
Firefox: 144.0.2
Firefox Developer Edition: 145.0
Safari: 26.0.1
Safari Technology Preview: 26.0
npmPackages:
vitest: 4.0.6 => 4.0.6Used Package Manager
pnpm
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- Read the Contributing Guidelines.
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- The provided reproduction is a minimal reproducible example of the bug.