Return Objects from fs.read & fs.write

[teledemic]

The promisified version of fs.read shows up in the typescript typings, but when run gives "fs.read is not a function". I'm using the latest versions of both:

		"fs-extra": "3.0.1",
		"@types/fs-extra": "3.0.2",

and calling as I would expect to:

let [bytesread, buffer] = await fs.read(fd, buf, 0, length, start);

[RyanZim]

This is due to the way our promisification logic works (or rather, doesn't work). The promise only returns bytesread, not the buffer. So usage would be:

let buf = Buffer.alloc(length)
let bytesread = await fs.read(fd, buf, 0, length, start)
// Use buf here

The reason for this is that fs.read calls the callback with 3 arguments, but our promisification logic only passes the second argument in the promise.

This is sub-optimal and should probably be fixed in the next major release. However, I'm thinking we should follow the lead of util.promisify's behavior. From the docs:

If this method [fs.read()] is invoked as its util.promisify()ed version, it returns a Promise for an object with bytesRead and buffer properties.

CC: @jprichardson @manidlou

[teledemic]

Thanks! That works great, and having two references to the same buffer was redundant anyway. The typescript defs are still showing it returning [number, Buffer], but that's not an issue for this repo.

[RyanZim]

Yeah, could submit a fix here: https://github.com/DefinitelyTyped/DefinitelyTyped