From 76c5dc995e7853dc871df118beaea31ced3528aa Mon Sep 17 00:00:00 2001
From: Ruben Bridgewater <ruben@bridgewater.de>
Date: Sun, 17 May 2020 05:20:08 +0200
Subject: [PATCH] repl: support optional chaining during autocompletion

This makes sure the autocompletion is able to handle optional
chaining notations.

Signed-off-by: Ruben Bridgewater <ruben@bridgewater.de>

PR-URL: https://github.com/nodejs/node/pull/33450
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
---
 lib/repl.js                             | 20 ++++++++++++--------
 test/parallel/test-repl-tab-complete.js | 13 +++++++++++++
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/lib/repl.js b/lib/repl.js
index 41aaf126e39b94..369c12852b42b2 100644
--- a/lib/repl.js
+++ b/lib/repl.js
@@ -1066,7 +1066,7 @@ REPLServer.prototype.turnOffEditorMode = deprecate(
 const requireRE = /\brequire\s*\(\s*['"`](([\w@./-]+\/)?(?:[\w@./-]*))(?![^'"`])$/;
 const fsAutoCompleteRE = /fs(?:\.promises)?\.\s*[a-z][a-zA-Z]+\(\s*["'](.*)/;
 const simpleExpressionRE =
-    /(?:[a-zA-Z_$](?:\w|\$)*\.)*[a-zA-Z_$](?:\w|\$)*\.?$/;
+    /(?:[a-zA-Z_$](?:\w|\$)*\??\.)*[a-zA-Z_$](?:\w|\$)*\??\.?$/;
 
 function isIdentifier(str) {
   if (str === '') {
@@ -1138,7 +1138,7 @@ function complete(line, callback) {
   line = line.trimLeft();
 
   // REPL commands (e.g. ".break").
-  let filter;
+  let filter = '';
   if (/^\s*\.(\w*)$/.test(line)) {
     completionGroups.push(ObjectKeys(this.commands));
     completeOn = line.match(/^\s*\.(\w*)$/)[1];
@@ -1253,10 +1253,8 @@ function complete(line, callback) {
     let expr;
     completeOn = (match ? match[0] : '');
     if (line.length === 0) {
-      filter = '';
       expr = '';
     } else if (line[line.length - 1] === '.') {
-      filter = '';
       expr = match[0].slice(0, match[0].length - 1);
     } else {
       const bits = match[0].split('.');
@@ -1285,6 +1283,12 @@ function complete(line, callback) {
       return;
     }
 
+    let chaining = '.';
+    if (expr[expr.length - 1] === '?') {
+      expr = expr.slice(0, -1);
+      chaining = '?.';
+    }
+
     const evalExpr = `try { ${expr} } catch {}`;
     this.eval(evalExpr, this.context, 'repl', (e, obj) => {
       if (obj != null) {
@@ -1316,12 +1320,12 @@ function complete(line, callback) {
       }
 
       if (memberGroups.length) {
-        for (let i = 0; i < memberGroups.length; i++) {
-          completionGroups.push(
-            memberGroups[i].map((member) => `${expr}.${member}`));
+        expr += chaining;
+        for (const group of memberGroups) {
+          completionGroups.push(group.map((member) => `${expr}${member}`));
         }
         if (filter) {
-          filter = `${expr}.${filter}`;
+          filter = `${expr}${filter}`;
         }
       }
 
diff --git a/test/parallel/test-repl-tab-complete.js b/test/parallel/test-repl-tab-complete.js
index c40485ce3f5eac..0511e32d0a9719 100644
--- a/test/parallel/test-repl-tab-complete.js
+++ b/test/parallel/test-repl-tab-complete.js
@@ -68,6 +68,19 @@ testMe.complete('console.lo', common.mustCall(function(error, data) {
   assert.deepStrictEqual(data, [['console.log'], 'console.lo']);
 }));
 
+testMe.complete('console?.lo', common.mustCall((error, data) => {
+  assert.deepStrictEqual(data, [['console?.log'], 'console?.lo']);
+}));
+
+testMe.complete('console?.zzz', common.mustCall((error, data) => {
+  assert.deepStrictEqual(data, [[], 'console?.zzz']);
+}));
+
+testMe.complete('console?.', common.mustCall((error, data) => {
+  assert(data[0].includes('console?.log'));
+  assert.strictEqual(data[1], 'console?.');
+}));
+
 // Tab Complete will return globally scoped variables
 putIn.run(['};']);
 testMe.complete('inner.o', common.mustCall(function(error, data) {