fix: Use the private value as long as it isn't undefined (#327)

Related: npm/cli#8246

Author: owlstronaut

lib/default-input.js

@@ -267,7 +267,8 @@ exports.type = yes ? type : prompt('type', type, (data) => {
   return data
 })
 
-const initPrivate = package.private || getConfig('private')
-if (initPrivate === true) {
-  exports.private = true
+// Only include private field if it already exists or if explicitly set in config
+const configPrivate = getConfig('private')
+if (package.private !== undefined || configPrivate !== undefined) {
+  exports.private = package.private !== undefined ? package.private : configPrivate
 }

test/private-defaults.js

@@ -18,7 +18,7 @@ t.test('private field with init-private false', async (t) => {
     config: { yes: 'yes', 'init-private': false },
   })
 
-  t.equal(data.private, undefined, 'private field set to false is undefined')
+  t.equal(data.private, false, 'private field set to false is undefined')
 })
 
 t.test('private field without init-private', async (t) => {
@@ -28,3 +28,47 @@ t.test('private field without init-private', async (t) => {
 
   t.equal(data.private, undefined, 'private not set in by default')
 })
+
+t.test('respects existing private field in package.json', async (t) => {
+  const { data } = await setup(t, __filename, {
+    testdir: {
+      'package.json': JSON.stringify({
+        name: 'existing-package',
+        version: '1.0.0',
+        private: true,
+      }),
+    },
+    config: { yes: 'yes' },
+  })
+
+  t.equal(data.private, true, 'keeps existing private value from package.json')
+})
+
+t.test('existing private field takes precedence over config', async (t) => {
+  const { data } = await setup(t, __filename, {
+    testdir: {
+      'package.json': JSON.stringify({
+        name: 'existing-package',
+        version: '1.0.0',
+        private: true,
+      }),
+    },
+    config: { yes: 'yes', 'init-private': false },
+  })
+
+  t.equal(data.private, true, 'existing package.json private field takes precedence over config')
+})
+
+t.test('adds private from config when existing package has no private field', async t => {
+  const { data } = await setup(t, __filename, {
+    testdir: {
+      'package.json': JSON.stringify({
+        name: 'existing-package',
+        version: '1.0.0',
+      }),
+    },
+    config: { yes: 'yes', 'init-private': true },
+  })
+
+  t.equal(data.private, true, 'adds private field from config when not in existing package')
+})