From 0a7e15415f3514a4baad064478c76f0c17e9548a Mon Sep 17 00:00:00 2001
From: mshanemc <shane.mclaughlin@salesforce.com>
Date: Wed, 12 Jul 2023 10:16:59 -0500
Subject: [PATCH] fix: flags omit undefined for boolean flags

---
 src/parser/parse.ts       |  3 ++-
 test/parser/parse.test.ts | 23 +++++++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/src/parser/parse.ts b/src/parser/parse.ts
index 218aa5051..e04d8fb75 100644
--- a/src/parser/parse.ts
+++ b/src/parser/parse.ts
@@ -346,8 +346,9 @@ export class Parser<T extends ParserInput, TFlags extends OutputFlags<T['flags']
 
     const valueReference = fwsArrayToObject(flagsWithValues.filter(fws => !fws.metadata?.setFromDefault))
 
-    const flagsWithAllValues = await Promise.all(flagsWithValues
+    const flagsWithAllValues = (await Promise.all(flagsWithValues
     .map(async fws => (fws.metadata?.setFromDefault ? {...fws, value: await fws.valueFunction?.(fws, valueReference)} : fws)))
+    ).filter(fws => fws.value !== undefined)
 
     const finalFlags = (flagsWithAllValues.some(fws => typeof fws.helpFunction === 'function')) ? await addDefaultHelp(flagsWithAllValues) : flagsWithAllValues
 
diff --git a/test/parser/parse.test.ts b/test/parser/parse.test.ts
index 62c8eaacf..06e3852a4 100644
--- a/test/parser/parse.test.ts
+++ b/test/parser/parse.test.ts
@@ -22,6 +22,29 @@ describe('parse', () => {
     expect(out).to.deep.include({flags: {bool: true}})
   })
 
+  describe('undefined flags', () => {
+    it('omits undefined flags when no flags', async () => {
+      const out = await parse([], {
+        flags: {
+          bool: Flags.boolean(),
+        },
+      })
+      expect(out.flags).to.deep.equal({})
+    })
+
+    it('omits undefined flags when some flags exist', async () => {
+      const out = await parse(['--bool', '--str', 'k'], {
+        flags: {
+          bool: Flags.boolean(),
+          bool2: Flags.boolean(),
+          str: Flags.string(),
+          str2: Flags.string(),
+        },
+      })
+      expect(out.flags).to.deep.equal({bool: true, str: 'k'})
+    })
+  })
+
   it('arg1', async () => {
     const out = await parse(['arg1'], {
       args: {foo: Args.string()},