From f25bbf12556eb5478ea876db825c230d1b1c650c Mon Sep 17 00:00:00 2001
From: Gerhard Stoebich <18708370+Flarna@users.noreply.github.com>
Date: Wed, 14 Aug 2019 22:35:41 +0200
Subject: [PATCH] readline: establish y in cursorTo as optional

Parameter y in cursorTo() is optional and this is also verified by
tests but docs don't state this. Besides that if the newly added
parameter callback is used with no y, it's quite unhandy. This PR allows
to simply omit y.

PR-URL: https://github.com/nodejs/node/pull/29128
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
---
 doc/api/readline.md                | 2 +-
 doc/api/tty.md                     | 2 +-
 lib/readline.js                    | 5 +++++
 test/parallel/test-readline-csi.js | 8 ++++++++
 4 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/doc/api/readline.md b/doc/api/readline.md
index 47dfad8dabb..43d3a7e8f62 100644
--- a/doc/api/readline.md
+++ b/doc/api/readline.md
@@ -487,7 +487,7 @@ function completer(linePartial, callback) {
 }
 ```
 
-## readline.cursorTo(stream, x, y[, callback])
+## readline.cursorTo(stream, x[, y][, callback])
 <!-- YAML
 added: v0.7.7
 changes:
diff --git a/doc/api/tty.md b/doc/api/tty.md
index 977576970c0..335aef7589b 100644
--- a/doc/api/tty.md
+++ b/doc/api/tty.md
@@ -145,7 +145,7 @@ added: v0.7.7
 A `number` specifying the number of columns the TTY currently has. This property
 is updated whenever the `'resize'` event is emitted.
 
-### writeStream.cursorTo(x, y[, callback])
+### writeStream.cursorTo(x[, y][, callback])
 <!-- YAML
 added: v0.7.7
 changes:
diff --git a/lib/readline.js b/lib/readline.js
index b741557a4d2..5b8fc6706c5 100644
--- a/lib/readline.js
+++ b/lib/readline.js
@@ -1193,6 +1193,11 @@ function cursorTo(stream, x, y, callback) {
   if (callback !== undefined && typeof callback !== 'function')
     throw new ERR_INVALID_CALLBACK(callback);
 
+  if (typeof y === 'function') {
+    callback = y;
+    y = undefined;
+  }
+
   if (stream == null || (typeof x !== 'number' && typeof y !== 'number')) {
     if (typeof callback === 'function')
       process.nextTick(callback);
diff --git a/test/parallel/test-readline-csi.js b/test/parallel/test-readline-csi.js
index c1f34f5a303..27bfd2bce51 100644
--- a/test/parallel/test-readline-csi.js
+++ b/test/parallel/test-readline-csi.js
@@ -133,6 +133,10 @@ writable.data = '';
 assert.strictEqual(readline.cursorTo(writable, 1, 'a'), true);
 assert.strictEqual(writable.data, '\x1b[2G');
 
+writable.data = '';
+assert.strictEqual(readline.cursorTo(writable, 1), true);
+assert.strictEqual(writable.data, '\x1b[2G');
+
 writable.data = '';
 assert.strictEqual(readline.cursorTo(writable, 1, 2), true);
 assert.strictEqual(writable.data, '\x1b[3;2H');
@@ -141,6 +145,10 @@ writable.data = '';
 assert.strictEqual(readline.cursorTo(writable, 1, 2, common.mustCall()), true);
 assert.strictEqual(writable.data, '\x1b[3;2H');
 
+writable.data = '';
+assert.strictEqual(readline.cursorTo(writable, 1, common.mustCall()), true);
+assert.strictEqual(writable.data, '\x1b[2G');
+
 // Verify that cursorTo() throws on invalid callback.
 assert.throws(() => {
   readline.cursorTo(writable, 1, 1, null);