Add cursorTo & clearLine to streams

[reyronald]

Using process.stdout.cursorTo and process.stdout.clearLine will error in Flow because those definitions are missing.

Error: src/db/seeds/utils/helpers.js:9
  9:   process.stdout.cursorTo(0)
                      ^^^^^^^^ property `cursorTo`. Property not found in
  9:   process.stdout.cursorTo(0)
       ^^^^^^^^^^^^^^ stream$Writable

Error: src/db/seeds/utils/helpers.js:9
  9:   process.stdout.cursorTo(0)
                      ^^^^^^^^ property `cursorTo`. Property not found in
  9:   process.stdout.cursorTo(0)
       ^^^^^^^^^^^^^^ tty$WriteStream

node/lib/readline.js
node/lib/tty.js

Error: src/db/seeds/utils/helpers.js:10
 10:   process.stdout.clearLine()
                      ^^^^^^^^^ property `clearLine`. Property not found in
 10:   process.stdout.clearLine()
       ^^^^^^^^^^^^^^ stream$Writable

Error: src/db/seeds/utils/helpers.js:10
 10:   process.stdout.clearLine()
                      ^^^^^^^^^ property `clearLine`. Property not found in
 10:   process.stdout.clearLine()
       ^^^^^^^^^^^^^^ tty$WriteStream

node/lib/readline.js
node/lib/tty.js

I'm not sure if I added them in the correct place, so please check and let me know.

[nmote]

Could you link API docs to support this change? If it's an undocumented API in Node (even though it does exist in the source) we would have to think twice about merging this.

[reyronald]

Hey @nmote , sure, should've done that from the get-go, sorry bout that!

I'm certain those are not undocumented APIs, I think this might be what you are looking for

• https://nodejs.org/api/readline.html#readline_readline_cursorto_stream_x_y
• https://nodejs.org/api/readline.html#readline_readline_clearline_stream_dir

Also, for context: nodejs/node-v0.x-archive#6948

[nmote]

We already have cursorTo and clearLine defined on the readline module (search for declare module "readline" in lib/node.js). It looks like that is what the docs you linked are referring to.

Since there aren't any docs which support this change, I'm going to close for now. Feel free to reopen if I have misunderstood something or if you find different docs.

[reyronald]

Hey @nmote ,

I guess then I should've linked to these docs instead, on the tty.WriteStream class (my bad):

• writeStream.cursorTo(x, y)
• writeStream.clearLine(dir)

There are for sure missing definitions for these two functions, I even found code on this repo itself using them when I was researching the issue after getting Flow errors on my project and before opening this PR:

flow/packages/flow-dev-tools/src/test/RunQueue.js

Lines 202 to 208 in 41b0eab

	if (this.isTTY) {
	// $FlowFixMe Add to lib
	process.stdout.moveCursor(0, -this.fancyStatusSize);
	// $FlowFixMe Add to lib
	process.stdout.cursorTo(0);
	// $FlowFixMe Add to lib
	process.stdout.clearLine();

flow/packages/flow-dev-tools/src/record/recordRunner.js

Lines 124 to 126 in 41b0eab

	if (process.stdout.isTTY) {
	// $FlowFixMe - Add this to lib file
	process.stdout.clearLine();

Also note that:

The tty.WriteStream class is a subclass of net.Socket that represents the writable side of a TTY. In normal circumstances, process.stdout and process.stderr will be the only tty.WriteStream instances created for a Node.js process and there should be no reason to create additional instances.
Source

I believe this is the pull request that merged the documentation for these functions on the Node repo: nodejs/node#22893

So I think this is still missing from Flow and should be addressed, but I can't re-open this issue apparently. Let me know what you think!

[facebook-github-bot]

@mroch has imported this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[facebook-github-bot]

@mroch merged this pull request in 4b30713.