Testing sharp with memfs error: [Error: Input file is missing]

I had trouble testing my code that implement sharp and memfs. I has codes that download image and cropping it to certain dimension. I use sharp to achieve the cropping. When it comes testing, I use jest and memfs. My test code has 2 parts:

1. Download a image and save to mock volume/fileSystem that created with memfs.
2. Cropping the downloaded image to certain dimension with sharp.

Part 1 worked perfectly, was able to download image to the fake volume and asserted with jest (exist in the fake volume).
But part 2 gave me error:[Error: Input file is missing].

const sizeToCrop = {
            width: 378,
            height: 538,
            left: 422,
            top: 0,
        };

sharp(`./downloadedImage.jpg`)
            .extract(sizeToCrop)
            .toFile(`./CroppedImage.jpg`)
            .then(() => {
                console.log(`resolve!`);
            })
            .catch((err: Error) => {
                console.log(err);
                return Promise.reject();
            });

// Error message: [Error: Input file is missing]

But when I test it with real volume. It worked fine.
Anyone has idea how to solve this? Thank you.

[lovell]

It looks like memfs is a memory-based filesystem, so you’ll probably need to use something like the following:

const { fs } = require('memfs');
const file = fs.readFileSync('./downloadedImage.jpg');
sharp(file)...

[ogmaro]

It looks like memfs is a memory-based filesystem;

This was helpful. I, however, used fs