readline: move escape codes into internal/readline

Moves escape codes into internal/readline for easier management.

PR-URL: https://github.com/nodejs/node/pull/12755
Reviewed-By: Anna Henningsen <anna@addaleax.net>

1 files changed, 20 insertions, 11 deletions

diff --git a/lib/readline.js b/lib/readline.js
index f46fc0d59c..60864f40af 100644
--- a/lib/readline.js
+++ b/lib/readline.js
@@ -31,12 +31,21 @@ const { debug, inherits } = require('util');
 const Buffer = require('buffer').Buffer;
 const EventEmitter = require('events');
 const {
+  CSI,
   emitKeys,
   getStringWidth,
   isFullWidthCodePoint,
   stripVTControlCharacters
 } = require('internal/readline');
 
+const {
+  kEscape,
+  kClearToBeginning,
+  kClearToEnd,
+  kClearLine,
+  kClearScreenDown
+} = CSI;
+
 const kHistorySize = 30;
 const kMincrlfDelay = 100;
 const kMaxcrlfDelay = 2000;
@@ -995,7 +1004,7 @@ function emitKeypressEvents(stream, iface) {
           try {
             stream[ESCAPE_DECODER].next(r[i]);
             // Escape letter at the tail position
-            if (r[i] === '\x1b' && i + 1 === r.length) {
+            if (r[i] === kEscape && i + 1 === r.length) {
               timeoutId = setTimeout(escapeCodeTimeout, ESCAPE_CODE_TIMEOUT);
             }
           } catch (err) {
@@ -1047,9 +1056,9 @@ function cursorTo(stream, x, y) {
     throw new Error('Can\'t set cursor row without also setting it\'s column');
 
   if (typeof y !== 'number') {
-    stream.write('\x1b[' + (x + 1) + 'G');
+    stream.write(CSI`${x + 1}G`);
   } else {
-    stream.write('\x1b[' + (y + 1) + ';' + (x + 1) + 'H');
+    stream.write(CSI`${y + 1};${x + 1}H`);
   }
 }
 
@@ -1062,15 +1071,15 @@ function moveCursor(stream, dx, dy) {
     return;
 
   if (dx < 0) {
-    stream.write('\x1b[' + (-dx) + 'D');
+    stream.write(CSI`${-dx}D`);
   } else if (dx > 0) {
-    stream.write('\x1b[' + dx + 'C');
+    stream.write(CSI`${dx}C`);
   }
 
   if (dy < 0) {
-    stream.write('\x1b[' + (-dy) + 'A');
+    stream.write(CSI`${-dy}A`);
   } else if (dy > 0) {
-    stream.write('\x1b[' + dy + 'B');
+    stream.write(CSI`${dy}B`);
   }
 }
 
@@ -1087,13 +1096,13 @@ function clearLine(stream, dir) {
 
   if (dir < 0) {
     // to the beginning
-    stream.write('\x1b[1K');
+    stream.write(kClearToBeginning);
   } else if (dir > 0) {
     // to the end
-    stream.write('\x1b[0K');
+    stream.write(kClearToEnd);
   } else {
     // entire line
-    stream.write('\x1b[2K');
+    stream.write(kClearLine);
   }
 }
 
@@ -1105,7 +1114,7 @@ function clearScreenDown(stream) {
   if (stream === null || stream === undefined)
     return;
 
-  stream.write('\x1b[0J');
+  stream.write(kClearScreenDown);
 }
 
 module.exports = {