readline: allow completer to rewrite existing input

Sometimes, it makes sense for a completer to change the existing input, e.g. by adjusting the casing (imagine a completer that corrects `Number.isNan` to `Number.IsNaN`, for example). This commit allows that in the readline implemention. PR-URL: #39178 Reviewed-By: Antoine du Hamel <[email protected]> Reviewed-By: Gus Caplan <[email protected]> Reviewed-By: Rich Trott <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: Tobias Nießen <[email protected]>

Author: addaleax

lib/readline.js

@@ -705,9 +705,21 @@ Interface.prototype._tabComplete = function(lastKeypressWasTab){
 // If there is a common prefix to all matches, then apply that portion.
 constprefix=commonPrefix(ArrayPrototypeFilter(completions,
 (e)=>e!==''));
-if(prefix.length>completeOn.length){
+if(StringPrototypeStartsWith(prefix,completeOn)&&
+prefix.length>completeOn.length){
 this._insertString(StringPrototypeSlice(prefix,completeOn.length));
 return;
+}elseif(!StringPrototypeStartsWith(completeOn,prefix)){
+this.line=StringPrototypeSlice(this.line,
+0,
+this.cursor-completeOn.length)+
+prefix+
+StringPrototypeSlice(this.line,
+this.cursor,
+this.line.length);
+this.cursor=this.cursor-completeOn.length+prefix.length;
+this._refreshLine();
+return;
 }
 
 if(!lastKeypressWasTab){

test/parallel/test-readline-tab-complete.js

@@ -100,3 +100,39 @@ common.skipIfDumbTerminal();
 });
 rli.close();
 }
+
+{
+letoutput='';
+classFakeInputextendsEventEmitter{
+columns=80
+
+write=common.mustCall((data)=>{
+output+=data;
+},9)
+
+resume(){}
+pause(){}
+end(){}
+}
+
+constfi=newFakeInput();
+constrli=newreadline.Interface({
+input: fi,
+output: fi,
+terminal: true,
+completer: common.mustCall((input,cb)=>{
+cb(null,[[input[0].toUpperCase()+input.slice(1)],input]);
+}),
+});
+
+rli.on('line',common.mustNotCall());
+fi.emit('data','input');
+queueMicrotask(()=>{
+fi.emit('data','\t');
+queueMicrotask(()=>{
+assert.match(output,/>Input/);
+output='';
+rli.close();
+});
+});
+}