TypeError: blob.text is not a function (nodeToFsa)

[StephanMeijer]

Cause

In my test I am using nodeToFsa¹ in order to 'mock' the Origin Private File System (OPFS)² API's that are available in the browser.

Application logic and tests can be found here.³

In OriginPrivateFileSystemStorage.load I am calling fileHandle.getFile()⁴. The expectation is that this function⁴ returns Promise<File>. Promise<File> was returned but the .text()⁵ method on File⁶ seems not to be properly implemented..

Reproduction

1. Checkout https://gitlab.com/toegang-voor-iedereen/frontend/editor-app:

$ git checkout [email protected]:toegang-voor-iedereen/frontend/editor-app.git
# or
$ git checkout https://gitlab.com/toegang-voor-iedereen/frontend/editor-app.git

2. run $ git checkout feature/NLD-264-opfs-memfs-issue
3. run $ npm ci
4. run $ npm run test -- src/storage/OriginPrivateFileSystemStorage.spec.ts

Versions

$ npm list | grep memfs
[email protected]
$ npm -v
10.8.2
$ node -v
v22.8.0

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Footnotes

1. https://github.com/streamich/memfs/blob/master/docs/fsa/fs-to-fsa.md ↩

2. https://developer.mozilla.org/en-US/docs/Web/API/File_System_API/Origin_private_file_system ↩

3. https://gitlab.com/toegang-voor-iedereen/frontend/editor-app/-/merge_requests/260 ↩

4. https://developer.mozilla.org/en-US/docs/Web/API/FileSystemFileHandle/getFile ↩ ↩²

5. https://developer.mozilla.org/en-US/docs/Web/API/Blob/text ↩

6. https://developer.mozilla.org/en-US/docs/Web/API/File#instance_methods ↩