readline: small refactoring

This just removes some redundant work and some other small things.

PR-URL: #31006
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

lib/readline.js

@@ -720,16 +720,16 @@ Interface.prototype._historyPrev = function() {
 Interface.prototype._getDisplayPos = function(str) {
   let offset = 0;
   const col = this.columns;
-  let row = 0;
+  let rows = 0;
   str = stripVTControlCharacters(str);
   for (let i = 0, len = str.length; i < len; i++) {
     const code = str.codePointAt(i);
     if (code >= kUTF16SurrogateThreshold) { // Surrogates.
       i++;
     }
     if (code === 0x0a) { // new line \n
-      // row must be incremented by 1 even if offset = 0 or col = +Infinity
-      row += MathCeil(offset / col) || 1;
+      // rows must be incremented by 1 even if offset = 0 or col = +Infinity
+      rows += MathCeil(offset / col) || 1;
       offset = 0;
       continue;
     }
@@ -744,17 +744,16 @@ Interface.prototype._getDisplayPos = function(str) {
     }
   }
   const cols = offset % col;
-  const rows = row + (offset - cols) / col;
-  return { cols: cols, rows: rows };
+  rows += (offset - cols) / col;
+  return { cols, rows };
 };
 
 
 // Returns current cursor's position and line
 Interface.prototype.getCursorPos = function() {
   const columns = this.columns;
   const strBeforeCursor = this._prompt + this.line.substring(0, this.cursor);
-  const dispPos = this._getDisplayPos(
-    stripVTControlCharacters(strBeforeCursor));
+  const dispPos = this._getDisplayPos(strBeforeCursor);
   let cols = dispPos.cols;
   let rows = dispPos.rows;
   // If the cursor is on a full-width character which steps over the line,
@@ -765,7 +764,7 @@ Interface.prototype.getCursorPos = function() {
     rows++;
     cols = 0;
   }
-  return { cols: cols, rows: rows };
+  return { cols, rows };
 };
 Interface.prototype._getCursorPos = Interface.prototype.getCursorPos;