WebAccess TypeError on write

[Seanw265]

WebAccessFS throws a type error on writeFileSync:

Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'buffer')

Here is a minimal reproduction of the issue:

Link to runnable example

import { configureSingle, fs } from "@zenfs/core";
import { WebAccess } from "@zenfs/dom";

console.log("clearing opfs");
await (await navigator.storage.getDirectory()).remove({ recursive: true });

const opfsRoot = await navigator.storage.getDirectory();

console.log("configuring");
await configureSingle({
  backend: WebAccess,
  handle: opfsRoot,
});
console.log("configured");

console.log("reading /", fs.readdirSync("/"));
try {
  console.log("writing /hello-world.txt");
  fs.writeFileSync("/hello-world.txt", "Hello world from provider worker!");
} catch (error) {
  console.error("Error writing /hello-world", error);
}
console.log("reading /", fs.readdirSync("/"));

The odd thing in this example is that the file does indeed seem to be written.

Here's the output I get:

'clearing opfs'
'configuring'
'configured'
'reading /' []
'writing /hello-world.txt'
Error writing /hello-world
'reading /' [ 'hello-world.txt' ]

[Seanw265]

Hmm something odd is that switching the writeFileSync for a writeFile with a callback results in no TypeError, but in this case, the file doesn't seem to be written at all. Running readdirSync after the write completes shows an empty directory.

link to example