Merge pull request #2032 from mauke/dom-nth-child

Fix :nth-child selector

Author: mergify[bot]

lib/Mojo/DOM/CSS.pm

@@ -117,11 +117,8 @@ sub _compile {
       # ":nth-*" (with An+B notation)
       $args = _equation($args) if $name =~ /^nth-/;
 
-      # ":first-*" (rewrite to ":nth-*")
-      ($name, $args) = ("nth-$1", [0, 1]) if $name =~ /^first-(.+)$/;
-
-      # ":last-*" (rewrite to ":nth-*")
-      ($name, $args) = ("nth-$name", [-1, 1]) if $name =~ /^last-/;
+      # ":first-*", ":last-*" (rewrite to ":nth-(last-)*")
+      ($name, $args) = ("nth-$+", [0, 1]) if $name =~ /^(?:first-(.+)|(last-.+))$/;
 
       push @$last, ['pc', $name, $args];
     }
@@ -144,7 +141,7 @@ sub _equation {
   return [0, 0] unless my $equation = shift;
 
   # "even"
-  return [2, 2] if $equation =~ /^\s*even\s*$/i;
+  return [2, 0] if $equation =~ /^\s*even\s*$/i;
 
   # "odd"
   return [2, 1] if $equation =~ /^\s*odd\s*$/i;
@@ -241,13 +238,16 @@ sub _pc {
   if (ref $args) {
     my $type     = $class eq 'nth-of-type' || $class eq 'nth-last-of-type' ? $current->[1] : undef;
     my @siblings = @{_siblings($current, $type)};
-    @siblings = reverse @siblings if $class eq 'nth-last-child' || $class eq 'nth-last-of-type';
-
+    my $index;
     for my $i (0 .. $#siblings) {
-      next if (my $result = $args->[0] * $i + $args->[1]) < 1;
-      return undef unless my $sibling = $siblings[$result - 1];
-      return 1 if $sibling eq $current;
+      $index = $i, last if $siblings[$i] eq $current;
     }
+    $index = $#siblings - $index if $class eq 'nth-last-child' || $class eq 'nth-last-of-type';
+    $index++;
+
+    my $delta = $index - $args->[1];
+    return 1 if $delta == 0;
+    return $args->[0] != 0 && ($delta < 0) == ($args->[0] < 0) && $delta % $args->[0] == 0;
   }
 
   # Everything else

t/mojo/dom.t

@@ -1040,28 +1040,28 @@ EOF
   is_deeply \@li, ['F'], 'found third last li element';
   @li = ();
   $dom->find('li:nth-child(1n+0)')->each(sub { push @li, shift->text });
-  is_deeply \@li, [qw(A B C D E F G)], 'found all li elements';
+  is_deeply \@li, [qw(A B C D E F G H)], 'found all li elements';
   @li = ();
   $dom->find('li:nth-child(1n-0)')->each(sub { push @li, shift->text });
-  is_deeply \@li, [qw(A B C D E F G)], 'found all li elements';
+  is_deeply \@li, [qw(A B C D E F G H)], 'found all li elements';
   @li = ();
   $dom->find('li:nth-child(n+0)')->each(sub { push @li, shift->text });
-  is_deeply \@li, [qw(A B C D E F G)], 'found all li elements';
+  is_deeply \@li, [qw(A B C D E F G H)], 'found all li elements';
   @li = ();
   $dom->find('li:nth-child(n)')->each(sub { push @li, shift->text });
-  is_deeply \@li, [qw(A B C D E F G)], 'found all li elements';
+  is_deeply \@li, [qw(A B C D E F G H)], 'found all li elements';
   @li = ();
   $dom->find('li:nth-child(n+0)')->each(sub { push @li, shift->text });
-  is_deeply \@li, [qw(A B C D E F G)], 'found all li elements';
+  is_deeply \@li, [qw(A B C D E F G H)], 'found all li elements';
   @li = ();
   $dom->find('li:NTH-CHILD(N+0)')->each(sub { push @li, shift->text });
-  is_deeply \@li, [qw(A B C D E F G)], 'found all li elements';
+  is_deeply \@li, [qw(A B C D E F G H)], 'found all li elements';
   @li = ();
   $dom->find('li:Nth-Child(N+0)')->each(sub { push @li, shift->text });
-  is_deeply \@li, [qw(A B C D E F G)], 'found all li elements';
+  is_deeply \@li, [qw(A B C D E F G H)], 'found all li elements';
   @li = ();
   $dom->find('li:nth-child(n)')->each(sub { push @li, shift->text });
-  is_deeply \@li, [qw(A B C D E F G)], 'found all li elements';
+  is_deeply \@li, [qw(A B C D E F G H)], 'found all li elements';
   @li = ();
   $dom->find('li:nth-child(0n+1)')->each(sub { push @li, shift->text });
   is_deeply \@li, [qw(A)], 'found first li element';
@@ -1102,19 +1102,19 @@ EOF
   is_deeply \@e, [qw(A E H)], 'found all odd li elements';
   @e = ();
   $dom->find('ul li:not(:first-child, :last-child)')->each(sub { push @e, shift->text });
-  is_deeply \@e, [qw(C E F H)], 'found all odd li elements';
+  is_deeply \@e, [qw(C E F H)], 'found all li elements but first/last';
   @e = ();
   $dom->find('ul li:is(:first-child, :last-child)')->each(sub { push @e, shift->text });
-  is_deeply \@e, [qw(A I)], 'found all odd li elements';
+  is_deeply \@e, [qw(A I)], 'found first/last li elements';
   @e = ();
   $dom->find('li:nth-last-of-type( odd )')->each(sub { push @e, shift->text });
-  is_deeply \@e, [qw(C F I)], 'found all odd li elements';
+  is_deeply \@e, [qw(C F I)], 'found all odd li elements (counting from end)';
   @e = ();
   $dom->find('p:nth-of-type(odd)')->each(sub { push @e, shift->text });
   is_deeply \@e, [qw(B G)], 'found all odd p elements';
   @e = ();
   $dom->find('p:nth-last-of-type(odd)')->each(sub { push @e, shift->text });
-  is_deeply \@e, [qw(B G)], 'found all odd li elements';
+  is_deeply \@e, [qw(B G)], 'found all odd p elements (counting from end)';
   @e = ();
   $dom->find('ul :nth-child(1)')->each(sub { push @e, shift->text });
   is_deeply \@e, ['A'], 'found first child';
@@ -1193,6 +1193,9 @@ EOF
   @e = ();
   $dom->find('div div:only-of-type')->each(sub { push @e, shift->text });
   is_deeply \@e, [qw(J K)], 'found only child';
+  @e = ();
+  $dom->find('div :nth-child(-n+2)')->each(sub { push @e, shift->text });
+  is_deeply \@e, [qw(J Mojo! K)], 'found first two children of each div';
 };
 
 subtest 'Links' => sub {