From e474c6776c4103ad1d48c8f58444bcf294980f51 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 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 81d9ce16472a6e..9e7e1b21ec8ffa 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);