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, 23 insertions, 4 deletions

diff --git a/lib/internal/readline.js b/lib/internal/readline.js
index 4474b02345..96da5cc82f 100644
--- a/lib/internal/readline.js
+++ b/lib/internal/readline.js
@@ -7,9 +7,27 @@
 const ansi =
   /[\u001b\u009b][[()#;?]*(?:[0-9]{1,4}(?:;[0-9]{0,4})*)?[0-9A-ORZcf-nqry=><]/g;
 
+const kEscape = '\x1b';
+
 var getStringWidth;
 var isFullWidthCodePoint;
 
+function CSI(strings, ...args) {
+  let ret = `${kEscape}[`;
+  for (var n = 0; n < strings.length; n++) {
+    ret += strings[n];
+    if (n < args.length)
+      ret += args[n];
+  }
+  return ret;
+}
+
+CSI.kEscape = kEscape;
+CSI.kClearToBeginning = CSI`1K`;
+CSI.kClearToEnd = CSI`0K`;
+CSI.kClearLine = CSI`2K`;
+CSI.kClearScreenDown = CSI`0J`;
+
 if (process.binding('config').hasIntl) {
   const icu = process.binding('icu');
   getStringWidth = function getStringWidth(str, options) {
@@ -151,11 +169,11 @@ function* emitKeys(stream) {
       shift: false
     };
 
-    if (ch === '\x1b') {
+    if (ch === kEscape) {
       escaped = true;
       s += (ch = yield);
 
-      if (ch === '\x1b') {
+      if (ch === kEscape) {
         s += (ch = yield);
       }
     }
@@ -370,7 +388,7 @@ function* emitKeys(stream) {
       // backspace or ctrl+h
       key.name = 'backspace';
       key.meta = escaped;
-    } else if (ch === '\x1b') {
+    } else if (ch === kEscape) {
       // escape key
       key.name = 'escape';
       key.meta = escaped;
@@ -409,5 +427,6 @@ module.exports = {
   emitKeys,
   getStringWidth,
   isFullWidthCodePoint,
-  stripVTControlCharacters
+  stripVTControlCharacters,
+  CSI
 };