Trim trailing whitespace in pre blocks in Markdown

src/browser/markdown.zig

@@ -36,24 +36,25 @@ const State = struct {
     list_depth: usize = 0,
     list_stack: [32]ListState = undefined,
     in_pre: bool = false,
+    pre_node: ?*Node = null,
     in_code: bool = false,
     in_blockquote: bool = false,
     in_table: bool = false,
     table_row_index: usize = 0,
     table_col_count: usize = 0,
     last_char_was_newline: bool = true,
-    };
+};
 
-    pub fn dump(node: *Node, opts: Opts, writer: *std.Io.Writer, page: *Page) !void {
+pub fn dump(node: *Node, opts: Opts, writer: *std.Io.Writer, page: *Page) !void {
     _ = opts;
     var state = State{};
     try render(node, &state, writer, page);
     if (!state.last_char_was_newline) {
         try writer.writeByte('\n');
     }
-    }
+}
 
-    fn render(node: *Node, state: *State, writer: *std.Io.Writer, page: *Page) anyerror!void {
+fn render(node: *Node, state: *State, writer: *std.Io.Writer, page: *Page) anyerror!void {
     switch (node._type) {
         .document, .document_fragment => {
             try renderChildren(node, state, writer, page);
@@ -63,21 +64,29 @@ const State = struct {
         },
         .cdata => |cd| {
             if (node.is(Node.CData.Text)) |_| {
-                    try renderText(cd.getData(), state, writer);
+                var text = cd.getData();
+                if (state.in_pre) {
+                    if (state.pre_node) |pre| {
+                        if (node.parentNode() == pre and node.nextSibling() == null) {
+                            text = std.mem.trimRight(u8, text, " \t\r\n");
+                        }
+                    }
+                }
+                try renderText(text, state, writer);
             }
         },
         else => {}, // Ignore other node types
     }
-    }
+}
 
-    fn renderChildren(parent: *Node, state: *State, writer: *std.Io.Writer, page: *Page) anyerror!void {
+fn renderChildren(parent: *Node, state: *State, writer: *std.Io.Writer, page: *Page) anyerror!void {
     var it = parent.childrenIterator();
     while (it.next()) |child| {
         try render(child, state, writer, page);
     }
-    }
+}
 
-    fn renderElement(el: *Element, state: *State, writer: *std.Io.Writer, page: *Page) anyerror!void {
+fn renderElement(el: *Element, state: *State, writer: *std.Io.Writer, page: *Page) anyerror!void {
     const tag = el.getTag();
 
     // Skip hidden/metadata elements
@@ -163,13 +172,15 @@ const State = struct {
             // Add spacing
             try writer.writeByte(' ');
         },
-            .blockquote => {            try writer.writeAll("> ");
+        .blockquote => {
+            try writer.writeAll("> ");
             state.in_blockquote = true;
             state.last_char_was_newline = false;
         },
         .pre => {
             try writer.writeAll("```\n");
             state.in_pre = true;
+            state.pre_node = el.asNode();
             state.last_char_was_newline = true;
         },
         .code => {
@@ -259,6 +270,7 @@ const State = struct {
             }
             try writer.writeAll("```\n");
             state.in_pre = false;
+            state.pre_node = null;
             state.last_char_was_newline = true;
         },
         .code => {