How to pass a Buffer as argument of fs.createReadStream

Question

According to docs https://nodejs.org/api/fs.html#fs_fs_createreadstream_path_options

fs.createReadStream() can accept Buffer as first argument

my node code:

Answer 1

The first argument to fs.createReadStream() must be the file path. You can apparently pass the path in a Buffer object, but it still must be an acceptable OS path when the Buffer is converted to a string.

It appears you are trying to pass the file content to fs.createReadStream(). That is not how that API works. If you look into the code for fs.createReadStream() it is completely clear in the code that it is going to call fs.open() and pass the first argument from fs.createReadStream() as the file path for fs.open().

If what you're trying to do is to create a readable stream from a buffer (no file involved), then you need to do that a different way. You can see how to do that here in this answer: Converting a Buffer into a ReadableStream in Node.js.

Conceptually, you just create a readable stream object, push the data you already have into it from your Buffer, push a null to signify the end of the stream and create a noop _read() method and you're done. You can then use that readable stream with any other code that expects to read it.