From 941e1bfb02fcf121fe593cd4150c4a4b6b9dd898 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: y in cursorTo is 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 by no y it's quite unhandy. This PR allows
to simply omit y.
---
 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 47dfad8dabb173..43d3a7e8f62dd4 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 977576970c0ea8..335aef7589b3bb 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 b741557a4d2337..5b8fc6706c500f 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 c1f34f5a303c97..27bfd2bce5173b 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);