readline: expose stream API in clearLine()

This commit adds an optional callback to clearLine(), which
is passed to the stream's write() method. It also exposes the
return value of write().

PR-URL: https://github.com/nodejs/node/pull/28674
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

1 files changed, 10 insertions, 12 deletions

diff --git a/lib/readline.js b/lib/readline.js
index d50b1d5a44..6a60df82c7 100644
--- a/lib/readline.js
+++ b/lib/readline.js
@@ -1234,20 +1234,18 @@ function moveCursor(stream, dx, dy) {
  *    0 for the entire line
  */
 
-function clearLine(stream, dir) {
-  if (stream === null || stream === undefined)
-    return;
+function clearLine(stream, dir, callback) {
+  if (callback !== undefined && typeof callback !== 'function')
+    throw new ERR_INVALID_CALLBACK(callback);
 
-  if (dir < 0) {
-    // to the beginning
-    stream.write(kClearToBeginning);
-  } else if (dir > 0) {
-    // to the end
-    stream.write(kClearToEnd);
-  } else {
-    // entire line
-    stream.write(kClearLine);
+  if (stream === null || stream === undefined) {
+    if (typeof callback === 'function')
+      process.nextTick(callback);
+    return true;
   }
+
+  const type = dir < 0 ? kClearToBeginning : dir > 0 ? kClearToEnd : kClearLine;
+  return stream.write(type, callback);
 }
 
 /**