repl: activate previews for lines exceeding the terminal columns

This improves the completion previews by activating them for lines
that exceed the current terminal columns.
As a drive-by fix it also simplifies some statements.
PR-URL: #31112
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: BridgeAR

lib/internal/repl/utils.js

@@ -136,14 +136,16 @@ function setupPreview(repl, contextSymbol, bufferSymbol, active) {
 
 functiongetPreviewPos(){
 constdisplayPos=repl._getDisplayPos(`${repl._prompt}${repl.line}`);
-constcursorPos=repl.getCursorPos();
-constrows=1+displayPos.rows-cursorPos.rows;
-return{ rows,cols: cursorPos.cols};
+constcursorPos=repl.line.length!==repl.cursor ?
+repl.getCursorPos() :
+displayPos;
+return{ displayPos, cursorPos };
 }
 
 constclearPreview=()=>{
 if(inputPreview!==null){
-const{ rows }=getPreviewPos();
+const{ displayPos, cursorPos }=getPreviewPos();
+constrows=displayPos.rows-cursorPos.rows+1;
 moveCursor(repl.output,0,rows);
 clearLine(repl.output);
 moveCursor(repl.output,0,-rows);
@@ -153,12 +155,25 @@ function setupPreview(repl, contextSymbol, bufferSymbol, active) {
 if(completionPreview!==null){
 // Prevent cursor moves if not necessary!
 constmove=repl.line.length!==repl.cursor;
+letpos,rows;
 if(move){
-cursorTo(repl.output,repl._prompt.length+repl.line.length);
+pos=getPreviewPos();
+cursorTo(repl.output,pos.displayPos.cols);
+rows=pos.displayPos.rows-pos.cursorPos.rows;
+moveCursor(repl.output,0,rows);
+}
+consttotalLine=`${repl._prompt}${repl.line}${completionPreview}`;
+constnewPos=repl._getDisplayPos(totalLine);
+// Minimize work for the terminal. It is enough to clear the right part of
+// the current line in case the preview is visible on a single line.
+if(newPos.rows===0||(pos&&pos.displayPos.rows===newPos.rows)){
+clearLine(repl.output,1);
+}else{
+clearScreenDown(repl.output);
 }
-clearLine(repl.output,1);
 if(move){
-cursorTo(repl.output,repl._prompt.length+repl.cursor);
+cursorTo(repl.output,pos.cursorPos.cols);
+moveCursor(repl.output,0,-rows);
 }
 completionPreview=null;
 }
@@ -198,17 +213,6 @@ function setupPreview(repl, contextSymbol, bufferSymbol, active) {
 
 constsuffix=prefix.slice(completeOn.length);
 
-consttotalLength=repl.line.length+
-repl._prompt.length+
-suffix.length+
-(repl.useColors ? 0 : 4);
-
-// TODO(BridgeAR): Fix me. This should not be necessary. See similar
-// comment in `showPreview()`.
-if(totalLength>repl.columns){
-return;
-}
-
 if(insertPreview){
 repl._insertString(suffix);
 return;
@@ -220,11 +224,17 @@ function setupPreview(repl, contextSymbol, bufferSymbol, active) {
 `\u001b[90m${suffix}\u001b[39m` :
 ` // ${suffix}`;
 
+const{ cursorPos, displayPos }=getPreviewPos();
 if(repl.line.length!==repl.cursor){
-cursorTo(repl.output,repl._prompt.length+repl.line.length);
+cursorTo(repl.output,displayPos.cols);
+moveCursor(repl.output,0,displayPos.rows-cursorPos.rows);
 }
 repl.output.write(result);
-cursorTo(repl.output,repl._prompt.length+repl.cursor);
+cursorTo(repl.output,cursorPos.cols);
+consttotalLine=`${repl._prompt}${repl.line}${suffix}`;
+constnewPos=repl._getDisplayPos(totalLine);
+constrows=newPos.rows-cursorPos.rows-(newPos.cols===0 ? 1 : 0);
+moveCursor(repl.output,0,-rows);
 });
 }
 
@@ -288,6 +298,7 @@ function setupPreview(repl, contextSymbol, bufferSymbol, active) {
 },()=>callback(newERR_INSPECTOR_NOT_AVAILABLE()));
 }
 
+// TODO(BridgeAR): Prevent previews while pasting code.
 constshowPreview=()=>{
 // Prevent duplicated previews after a refresh.
 if(inputPreview!==null){
@@ -373,12 +384,12 @@ function setupPreview(repl, contextSymbol, bufferSymbol, active) {
 `\u001b[90m${inspected}\u001b[39m` :
 `// ${inspected}`;
 
-const{rows: previewRows,cols: cursorCols}=getPreviewPos();
-if(previewRows!==1)
-moveCursor(repl.output,0,previewRows-1);
+const{cursorPos, displayPos}=getPreviewPos();
+constrows=displayPos.rows-cursorPos.rows;
+moveCursor(repl.output,0,rows);
 const{cols: resultCols}=repl._getDisplayPos(result);
 repl.output.write(`\n${result}`);
-moveCursor(repl.output,cursorCols-resultCols,-previewRows);
+moveCursor(repl.output,cursorPos.cols-resultCols,-rows-1);
 });
 };
 
@@ -452,8 +463,8 @@ function setupReverseSearch(repl) {
 // Reset the already matched set in case the direction is changed. That
 // way it's possible to find those entries again.
 alreadyMatched.clear();
+dir=keyName;
 }
-dir=keyName;
 returntrue;
 }
 
@@ -598,16 +609,14 @@ function setupReverseSearch(repl) {
 
 // Clear screen and write the current repl.line before exiting.
 cursorTo(repl.output,promptPos.cols);
-if(promptPos.rows!==0)
-moveCursor(repl.output,0,promptPos.rows);
+moveCursor(repl.output,0,promptPos.rows);
 clearScreenDown(repl.output);
 if(repl.line!==''){
 repl.output.write(repl.line);
 if(repl.line.length!==repl.cursor){
 const{ cols, rows }=repl.getCursorPos();
 cursorTo(repl.output,cols);
-if(rows!==0)
-moveCursor(repl.output,0,rows);
+moveCursor(repl.output,0,rows);
 }
 }
 }

test/parallel/test-repl-history-navigation.js

@@ -201,6 +201,9 @@ const tests = [
 // 236 + 2 + 4 + 8
 '\x1B[1G','\x1B[0J',
 `${prompt}${' '.repeat(236)} fun`,'\x1B[243G',
+' // ction','\x1B[243G',
+' // ction','\x1B[243G',
+'\x1B[0K',
 // 2. UP
 '\x1B[1G','\x1B[0J',
 `${prompt}${' '.repeat(235)} fun`,'\x1B[242G',