par(md): skip empty line...

... instead of clearing new line character

par/md.test.ts

@@ -7,12 +7,13 @@ const ren = new HtmlStrRenderer();
 // Misc
 
 Deno.test({
-  name: "should skip new line character",
+  name: "should skip empty line",
   fn: () => {
     const par = new MarkdownParser();
     assertEquals(ren.render(par.parse("\n")), "");
     assertEquals(ren.render(par.parse("\r\n")), "");
     assertEquals(ren.render(par.parse("\n\r\n")), "");
+    assertEquals(ren.render(par.parse("\n          \n")), "");
   },
 });
 
@@ -51,13 +52,12 @@ Deno.test({
 
 Deno.test({
   name: "should parse ATX header if line contains additional spaces",
+  only: true,
   fn: () => {
     const par = new MarkdownParser();
     assertEquals(ren.render(par.parse(" # hello")), "<h1>hello</h1>");
     assertEquals(ren.render(par.parse("  # hello")), "<h1>hello</h1>");
     assertEquals(ren.render(par.parse("   # hello")), "<h1>hello</h1>");
-    assertEquals(ren.render(par.parse("\n   # hello")), "<h1>hello</h1>");
-    assertEquals(ren.render(par.parse("\r\n   # hello")), "<h1>hello</h1>");
   },
 });
 

par/md.ts

@@ -2,7 +2,7 @@ import { AnyNode, Elem, Fragment, TextNode } from "../core/node.ts";
 import { isNil } from "../core/utils.ts";
 import { Parser } from "./types.ts";
 
-const RE_NEW_LINE = /^\r?\n/;
+const RE_EMPTY_LINE = /^\s*$/;
 
 const RE_OPEN_ATX_HEADING = /^\s{0,3}(#{1,6})(\s|$)/;
 const RE_CLOSE_ATX_HEADING = /(^|\s+)#*\s*$/;
@@ -12,17 +12,9 @@ export class MarkdownParser implements Parser {
     const astDoc: AstDocument = { kind: AstKind.Document, content: [] };
 
     let readStr = input;
-
     while (readStr.length) {
-      // 1. clear new line character
+      const newReadStr = skipEmptyLine(readStr) ??
-      const match = RE_NEW_LINE.exec(readStr);
+        parseAtxHeading(astDoc, readStr) ??
-      if (!isNil(match)) {
-        readStr = readStr.slice(match[0].length);
-        continue;
-      }
-
-      // 2. try to find atx heading sequence
-      const newReadStr = parseAtxHeading(astDoc, readStr) ??
         parseParagraph(astDoc, readStr);
       if (isNil(newReadStr)) break;
       readStr = newReadStr;
@@ -55,6 +47,12 @@ function Text(ast: AstText): TextNode {
 
 // parse utils
 
+function skipEmptyLine(readStr: string): string | null {
+  const match = RE_EMPTY_LINE.exec(readStr);
+  if (isNil(match)) return null;
+  return readStr.slice(match[0].length);
+}
+
 function parseAtxHeading(ast: AstDocument, readStr: string): string | null {
   const match = RE_OPEN_ATX_HEADING.exec(readStr);
   if (isNil(match)) return null;