Change to never match multiple ids

This matches CSS.

Author: wooorm

lib/id.js

@@ -17,7 +17,7 @@ import {ok as assert} from 'devlop'
  *   Whether `element` matches `query`.
  */
 export function id(query, element) {
-  assert(query.ids, 'expected `ids`')
-  const id = query.ids[query.ids.length - 1]
-  return Boolean(element.properties.id === id)
+  const ids = query.ids
+  assert(ids, 'expected `ids`')
+  return ids.length === 1 && element.properties.id === ids[0]
 }

test/matches.js

@@ -183,19 +183,13 @@ test('select.matches()', async function (t) {
       assert.ok(!matches('#two', h('#one')))
     })
 
-    await t.test(
-      'should prefer the last id if multiple id’s are specified (1)',
-      async function () {
-        assert.ok(matches('#two#one', h('#one')))
-      }
-    )
+    await t.test('should never match multiple ids (#1)', async function () {
+      assert.ok(!matches('#a#x', h('#a')))
+    })
 
-    await t.test(
-      'should prefer the last id if multiple id’s are specified (2)',
-      async function () {
-        assert.ok(!matches('#one#two', h('#one')))
-      }
-    )
+    await t.test('should never match multiple ids (#2)', async function () {
+      assert.ok(!matches('#a#x', h('#x')))
+    })
   })
 
   await t.test('class: `.class`', async function (t) {