From 414d1f78e1ec306ef6af99f9574491ff128d37b3 Mon Sep 17 00:00:00 2001
From: Titus Wormer <tituswormer@gmail.com>
Date: Thu, 29 Jun 2023 19:44:05 +0200
Subject: [PATCH] Change to yield `undefined` instead of `null`

---
 index.js       |  5 ++---
 readme.md      |  2 +-
 test/select.js | 20 ++++++++++----------
 3 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/index.js b/index.js
index 7328dcf..80ef621 100644
--- a/index.js
+++ b/index.js
@@ -44,7 +44,7 @@ export function matches(selector, node) {
  *   CSS selector, such as (`heading`, `link, linkReference`).
  * @param {Node | NodeLike | null | undefined} [tree]
  *   Tree to search.
- * @returns {Node | null}
+ * @returns {Node | undefined}
  *   First node in `tree` that matches `selector` or `null` if nothing is
  *   found.
  *
@@ -54,8 +54,7 @@ export function select(selector, tree) {
   const state = createState(selector, tree)
   state.one = true
   walk(state, tree || undefined)
-  // To do next major: return `undefined`.
-  return state.results[0] || null
+  return state.results[0]
 }
 
 /**
diff --git a/readme.md b/readme.md
index b284c6e..36b8d4f 100644
--- a/readme.md
+++ b/readme.md
@@ -150,7 +150,7 @@ Searches the tree in *[preorder][]*.
 
 ###### Returns
 
-First node in `tree` that matches `selector` or `null` if nothing is found.
+First node in `tree` that matches `selector` or `undefined` if nothing is found.
 
 This could be `tree` itself.
 
diff --git a/test/select.js b/test/select.js
index adff76e..6b2d218 100644
--- a/test/select.js
+++ b/test/select.js
@@ -76,7 +76,7 @@ test('select.select()', async function (t) {
     )
 
     await t.test('should yield nothing if not given a node', async function () {
-      assert.equal(select('*'), null)
+      assert.equal(select('*'), undefined)
     })
 
     await t.test('should yield the node if given a node', async function () {
@@ -184,7 +184,7 @@ test('select.select()', async function (t) {
             u('b', 'Delta')
           ])
         ),
-        null
+        undefined
       )
     })
   })
@@ -227,7 +227,7 @@ test('select.select()', async function (t) {
           'c ~ b',
           u('a', [u('b', 'Alpha'), u('c', 'Bravo'), u('d', 'Charlie')])
         ),
-        null
+        undefined
       )
     })
   })
@@ -258,7 +258,7 @@ test('select.select()', async function (t) {
               'c:first-child',
               u('a', [u('b', 'Alpha'), u('c', 'Bravo'), u('d', 'Charlie')])
             ),
-            null
+            undefined
           )
         }
       )
@@ -289,7 +289,7 @@ test('select.select()', async function (t) {
               'c:last-child',
               u('a', [u('b', 'Alpha'), u('c', 'Bravo'), u('d', 'Charlie')])
             ),
-            null
+            undefined
           )
         }
       )
@@ -320,7 +320,7 @@ test('select.select()', async function (t) {
               'c:only-child',
               u('a', [u('b', 'Alpha'), u('c', 'Bravo'), u('d', 'Charlie')])
             ),
-            null
+            undefined
           )
         }
       )
@@ -676,7 +676,7 @@ test('select.select()', async function (t) {
       )
 
       await t.test('should return nothing without matches', async function () {
-        assert.equal(select('b:first-of-type', u('a', [])), null)
+        assert.equal(select('b:first-of-type', u('a', [])), undefined)
       })
     })
 
@@ -702,7 +702,7 @@ test('select.select()', async function (t) {
       )
 
       await t.test('should return nothing without matches', async function () {
-        assert.equal(select('b:last-of-type', u('a', [])), null)
+        assert.equal(select('b:last-of-type', u('a', [])), undefined)
       })
     })
 
@@ -737,13 +737,13 @@ test('select.select()', async function (t) {
                 u('c', 'Foxtrot')
               ])
             ),
-            null
+            undefined
           )
         }
       )
 
       await t.test('should return nothing without matches', async function () {
-        assert.equal(select('b:only-of-type', u('a', [])), null)
+        assert.equal(select('b:only-of-type', u('a', [])), undefined)
       })
     })