From 4a41d16022f041d256eb8515e0c563f0fd5c8fbc Mon Sep 17 00:00:00 2001
From: John Gee <john@ruru.gen.nz>
Date: Tue, 25 Jan 2022 18:34:23 +1300
Subject: [PATCH] fix: support single dash as positional

---
 README.md     |  2 +-
 index.js      | 11 ++++++++---
 test/index.js | 10 ++++++++++
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index e11fcfa..bf7884e 100644
--- a/README.md
+++ b/README.md
@@ -202,7 +202,7 @@ const { flags, values, positionals } = parseArgs(argv, options);
   - the first flag would be parsed as `'-foo'`
   - the second flag would be parsed as `'foo'`
 - Is `-` a positional? ie, `bash some-test.sh | tap -`
-  - no
+  - yes
 
 [coverage-image]: https://img.shields.io/nycrc/pkgjs/parseargs
 [coverage-url]: https://github.com/pkgjs/parseargs/blob/main/.nycrc
diff --git a/index.js b/index.js
index ae746eb..41c1758 100644
--- a/index.js
+++ b/index.js
@@ -93,9 +93,14 @@ const parseArgs = (
     let arg = argv[pos];
 
     if (StringPrototypeStartsWith(arg, '-')) {
-      // Everything after a bare '--' is considered a positional argument
-      // and is returned verbatim
-      if (arg === '--') {
+      if (arg === '-') {
+        // '-' commonly used to represent stdin/stdout, treat as positional
+        result.positionals = ArrayPrototypeConcat(result.positionals, '-');
+        ++pos;
+        continue;
+      } else if (arg === '--') {
+        // Everything after a bare '--' is considered a positional argument
+        // and is returned verbatim
         result.positionals = ArrayPrototypeConcat(
           result.positionals,
           ArrayPrototypeSlice(argv, ++pos)
diff --git a/test/index.js b/test/index.js
index 1208a98..723f62f 100644
--- a/test/index.js
+++ b/test/index.js
@@ -47,6 +47,16 @@ test('args equals are passed "withValue"', function(t) {
   t.end();
 });
 
+test('when args include single dash then result stores dash as positional', function(t) {
+  const passedArgs = ['-'];
+  const expected = { flags: { }, values: { }, positionals: ['-'] };
+  const args = parseArgs(passedArgs);
+
+  t.deepEqual(args, expected);
+
+  t.end();
+});
+
 test('same arg is passed twice "withValue" and last value is recorded', function(t) {
   const passedArgs = ['--foo=a', '--foo', 'b'];
   const passedOptions = { withValue: ['foo'] };