From b070dc07a4cd75c1f2ddbb70816bebc30aa23769 Mon Sep 17 00:00:00 2001
From: Anatolii Sieryi <jacobator@gmail.com>
Date: Fri, 26 Feb 2021 16:57:43 +0200
Subject: [PATCH 1/2] feat: allow to access output of default completion in
 custom completion

---
 lib/completion.ts | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/completion.ts b/lib/completion.ts
index 207028831..e6e8634e3 100644
--- a/lib/completion.ts
+++ b/lib/completion.ts
@@ -193,7 +193,8 @@ export class Completion implements CompletionInstance {
       return (this.customCompletionFunction as FallbackCompletionFunction)(
         current,
         argv,
-        () => this.defaultCompletion(args, argv, current, done),
+        (onCompleted = done) =>
+          this.defaultCompletion(args, argv, current, onCompleted),
         completions => {
           done(null, completions);
         }
@@ -278,7 +279,7 @@ interface FallbackCompletionFunction {
   (
     current: string,
     argv: Arguments,
-    defaultCompletion: () => any,
+    defaultCompletion: (onCompleted?: CompletionCallback) => any,
     done: (completions: string[]) => any
   ): any;
 }

From 3b4f9cdd1d3fec33fb564e43d873701539c6544d Mon Sep 17 00:00:00 2001
From: Anatolii Sieryi <jacobator@gmail.com>
Date: Sun, 28 Feb 2021 22:25:30 +0200
Subject: [PATCH 2/2] chore: rename defaultCompletion -> completionFilter, add
 test

---
 lib/completion.ts   |  2 +-
 test/completion.cjs | 37 +++++++++++++++++++++++++++++++++----
 2 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/lib/completion.ts b/lib/completion.ts
index e6e8634e3..1a9075696 100644
--- a/lib/completion.ts
+++ b/lib/completion.ts
@@ -279,7 +279,7 @@ interface FallbackCompletionFunction {
   (
     current: string,
     argv: Arguments,
-    defaultCompletion: (onCompleted?: CompletionCallback) => any,
+    completionFilter: (onCompleted?: CompletionCallback) => any,
     done: (completions: string[]) => any
   ): any;
 }
diff --git a/test/completion.cjs b/test/completion.cjs
index 9fc774bd3..10b90661c 100644
--- a/test/completion.cjs
+++ b/test/completion.cjs
@@ -341,7 +341,7 @@ describe('Completion', () => {
       r.logs.should.include('success!');
     });
 
-    it('allows the custom completion function to use the standard one', done => {
+    it('allows the custom completion function to use the default completion w/o filter', done => {
       checkUsage(
         () => {
           yargs(['./completion', '--get-yargs-completions'])
@@ -349,8 +349,8 @@ describe('Completion', () => {
             .command('apple', 'banana')
             .completion(
               'completion',
-              (current, argv, defaultCompletion, done) => {
-                defaultCompletion();
+              (current, argv, completionFilter, done) => {
+                completionFilter();
               }
             )
             .parse();
@@ -365,6 +365,35 @@ describe('Completion', () => {
       );
     });
 
+    it('allows custom completion to be combined with default completion, using filter', done => {
+      checkUsage(
+        () => {
+          yargs(['./completion', '--get-yargs-completions'])
+            .command('foo', 'bar')
+            .command('apple', 'banana')
+            .completion(
+              'completion',
+              (current, argv, completionFilter, done) => {
+                completionFilter((err, completions) => {
+                  const filteredCompletions = completions.filter(
+                    completion => completion === 'foo'
+                  );
+                  done(filteredCompletions);
+                });
+              }
+            )
+            .parse();
+        },
+        null,
+        (err, r) => {
+          if (err) throw err;
+          r.logs.should.include('foo');
+          r.logs.should.not.include('apple');
+          return done();
+        }
+      );
+    });
+
     it('allows calling callback instead of default completion function', done => {
       checkUsage(
         () => {
@@ -373,7 +402,7 @@ describe('Completion', () => {
             .command('apple', 'banana')
             .completion(
               'completion',
-              (current, argv, defaultCompletion, done) => {
+              (current, argv, completionFilter, done) => {
                 done(['orange']);
               }
             )