From 43e1003131c0bb79ca8d80953b4a79956d7e8776 Mon Sep 17 00:00:00 2001
From: Jithil P Ponnan <jithil@outlook.com>
Date: Sun, 19 Jun 2022 16:32:26 +0530
Subject: [PATCH] repl: add cls command

repl: add cls command
`.cls` will clear the current repl screen
---
 doc/api/repl.md                        |  1 +
 lib/repl.js                            | 16 ++++++++++++++++
 test/parallel/test-repl-cls-command.js | 22 ++++++++++++++++++++++
 test/parallel/test-repl.js             |  1 +
 4 files changed, 40 insertions(+)
 create mode 100644 test/parallel/test-repl-cls-command.js

diff --git a/doc/api/repl.md b/doc/api/repl.md
index c120bb25efff29..b15fd7ea166b92 100644
--- a/doc/api/repl.md
+++ b/doc/api/repl.md
@@ -43,6 +43,7 @@ The following special commands are supported by all REPL instances:
   further input or processing of that expression.
 * `.clear`: Resets the REPL `context` to an empty object and clears any
   multi-line expression being input.
+* `.cls`: Clear the screen (or press <kbd>Ctrl</kbd>+<kbd>L</kbd>).
 * `.exit`: Close the I/O stream, causing the REPL to exit.
 * `.help`: Show this list of special commands.
 * `.save`: Save the current REPL session to a file:
diff --git a/lib/repl.js b/lib/repl.js
index fbe85c7b89c0a6..610718a8b48633 100644
--- a/lib/repl.js
+++ b/lib/repl.js
@@ -199,6 +199,12 @@ const {
   kAddNewLineOnTTY,
   kLastCommandErrored,
 } = require('internal/readline/interface');
+
+const {
+  clearScreenDown,
+  cursorTo,
+} = require('internal/readline/callbacks');
+
 let nextREPLResourceNumber = 1;
 // This prevents v8 code cache from getting confused and using a different
 // cache from a resource of the same name
@@ -2144,6 +2150,16 @@ function defineDefaultCommands(repl) {
       this.displayPrompt();
     },
   });
+
+  repl.defineCommand('cls', {
+    help: 'Clear the screen',
+    action: function() {
+      cursorTo(this.output, 0, 0);
+      clearScreenDown(this.output);
+      this.displayPrompt();
+    },
+  });
+
   if (repl.terminal) {
     repl.defineCommand('editor', {
       help: 'Enter editor mode',
diff --git a/test/parallel/test-repl-cls-command.js b/test/parallel/test-repl-cls-command.js
new file mode 100644
index 00000000000000..1b88ccee02f350
--- /dev/null
+++ b/test/parallel/test-repl-cls-command.js
@@ -0,0 +1,22 @@
+'use strict';
+
+require('../common');
+const assert = require('assert');
+const repl = require('repl');
+const ArrayStream = require('../common/arraystream');
+
+// eslint-disable-next-line no-control-regex
+const clearChar = /\[1;1H\u001b\[0J>/;
+let accum = '';
+const output = new ArrayStream();
+output.write = (data) => (accum += data.replace('\r', ''));
+
+const r = repl.start({
+  input: new ArrayStream(),
+  output,
+});
+['new Error', 'Promise'].forEach((cmd) => r.write(`${cmd}\n`));
+assert.strictEqual(accum.match(clearChar), null);
+r.write('.cls\n');
+assert.strictEqual(accum.match(clearChar).length > 0, true);
+r.write('.exit\n');
diff --git a/test/parallel/test-repl.js b/test/parallel/test-repl.js
index 5e4fac12723b73..b1e2b9c3689c0f 100644
--- a/test/parallel/test-repl.js
+++ b/test/parallel/test-repl.js
@@ -493,6 +493,7 @@ const errorTests = [
     expect: [
       /\.break/,
       /\.clear/,
+      /\.cls/,
       /\.exit/,
       /\.help/,
       /\.load/,