Oops, something went wrong in FS operation.

@ffmpeg/ffmpeg 0.9.8
@ffmpeg/core 0.8.5

the following error happened when run in chrome browser.
can anyone give some help.

-------source------
let ffmpeg = FFmpeg.createFFmpeg({
corePath: './ffmpeg-core.js',
log: true
});
await ffmpeg.load();
var videobr = [0,1,1,1,0];
ffmpeg.FS('writeFile', 'test.v', new Uint8Array(videobr, 0, videobr.byteLength));

--------log----------

log.js:15 [info] use ffmpeg.wasm v0.9.8
log.js:15 [info] load ffmpeg-core
log.js:15 [info] loading ffmpeg-core
log.js:15 [info] fetch http://localhost:8090/pubutils/ffmpeg-core.js
log.js:15 [info] http://localhost:8090/pubutils/ffmpeg-core.js file size = 105830 bytes
log.js:15 [info] http://localhost:8090/pubutils/ffmpeg-core.js blob URL = blob:http://localhost:8090/b971590d-29e1-4894-80db-505abe1a5bd1
log.js:15 [info] fetch http://localhost:8090/pubutils/ffmpeg-core.wasm
log.js:15 [info] http://localhost:8090/pubutils/ffmpeg-core.wasm file size = 23557464 bytes
log.js:15 [info] http://localhost:8090/pubutils/ffmpeg-core.wasm blob URL = blob:http://localhost:8090/69a76927-b3bd-40c6-bf87-cd46a9d26c36
log.js:15 [info] fetch http://localhost:8090/pubutils/ffmpeg-core.worker.js
log.js:15 [info] http://localhost:8090/pubutils/ffmpeg-core.worker.js file size = 3609 bytes
log.js:15 [info] http://localhost:8090/pubutils/ffmpeg-core.worker.js blob URL = blob:http://localhost:8090/546436fc-98c6-440d-8213-9c7d2e634788
log.js:15 [info] ffmpeg-core.js script loaded
log.js:15 [info] ffmpeg-core loaded
log.js:15 [info] run FS.writeFile test.v <5 bytes binary file>
createFFmpeg.js:167 Uncaught (in promise) Error: Oops, something went wrong in FS operation.
at Object._ [as FS] (createFFmpeg.js:167)
at ....