| 1 | /** |
| 2 | * Markdown to HTML parser |
| 3 | * Refactored for better readability and maintainability |
| 4 | */ |
| 5 | |
| 6 | /** |
| 7 | * Wraps text with HTML tags |
| 8 | * @param {string} text - Text to wrap |
| 9 | * @param {string} tag - HTML tag to use |
| 10 | * @returns {string} - Text wrapped in HTML tags |
| 11 | */ |
| 1 | 12 | function wrap(text, tag) { |
| 2 | 13 | return `<${tag}>${text}</${tag}>`; |
| 3 | 14 | } |
| 4 | 15 | |
| 5 | | function isTag(text, tag) { |
| 6 | | return text.startsWith(`<${tag}>`); |
| 7 | | } |
| 8 | | |
| 9 | | function parser(markdown, delimiter, tag) { |
| 10 | | const pattern = new RegExp(`${delimiter}(.+)${delimiter}`); |
| 11 | | const replacement = `<${tag}>$1</${tag}>`; |
| 12 | | return markdown.replace(pattern, replacement); |
| 13 | | } |
| 14 | | |
| 15 | | function parse__(markdown) { |
| 16 | | return parser(markdown, '__', 'strong'); |
| 16 | /** |
| 17 | * Parses bold text (__) to <strong> tags |
| 18 | * @param {string} markdown - Markdown text |
| 19 | * @returns {string} - HTML with bold tags |
| 20 | */ |
| 21 | function parseBold(markdown) { |
| 22 | const pattern = /__(.+)__/g; |
| 23 | return markdown.replace(pattern, '<strong>$1</strong>'); |
| 17 | 24 | } |
| 18 | 25 | |
| 19 | | function parse_(markdown) { |
| 20 | | return parser(markdown, '_', 'em'); |
| 26 | /** |
| 27 | * Parses italic text (_) to <em> tags |
| 28 | * @param {string} markdown - Markdown text |
| 29 | * @returns {string} - HTML with italic tags |
| 30 | */ |
| 31 | function parseItalic(markdown) { |
| 32 | const pattern = /_(.+)_/g; |
| 33 | return markdown.replace(pattern, '<em>$1</em>'); |
| 21 | 34 | } |
| 22 | 35 | |
| 23 | | function parseText(markdown, list) { |
| 24 | | const parsedText = parse_(parse__(markdown)); |
| 25 | | if (list) { |
| 26 | | return parsedText; |
| 27 | | } else { |
| 28 | | return wrap(parsedText, 'p'); |
| 29 | | } |
| 36 | /** |
| 37 | * Parses inline formatting (bold and italic) |
| 38 | * @param {string} markdown - Markdown text |
| 39 | * @returns {string} - HTML with inline formatting |
| 40 | */ |
| 41 | function parseInlineFormatting(markdown) { |
| 42 | return parseItalic(parseBold(markdown)); |
| 30 | 43 | } |
| 31 | 44 | |
| 32 | | function parseHeader(markdown, list) { |
| 33 | | let count = 0; |
| 34 | | for (let i = 0; i < markdown.length; i++) { |
| 35 | | if (markdown[i] === '#') { |
| 36 | | count += 1; |
| 37 | | } else { |
| 38 | | break; |
| 39 | | } |
| 40 | | } |
| 41 | | if (count === 0 || count > 6) { |
| 42 | | return [null, list]; |
| 45 | /** |
| 46 | * Parses a header line (# Header) to <h1>-<h6> tags |
| 47 | * @param {string} line - Markdown header line |
| 48 | * @returns {string|null} - HTML header or null if not a header |
| 49 | */ |
| 50 | function parseHeader(line) { |
| 51 | // Count leading # characters |
| 52 | let level = 0; |
| 53 | while (level < line.length && line[level] === '#') { |
| 54 | level++; |
| 43 | 55 | } |
| 44 | | const headerTag = `h${count}`; |
| 45 | | const headerHtml = wrap(markdown.substring(count + 1), headerTag); |
| 46 | | if (list) { |
| 47 | | return [`</ul>${headerHtml}`, false]; |
| 48 | | } else { |
| 49 | | return [headerHtml, false]; |
| 56 | |
| 57 | // Valid headers have 1-6 # characters |
| 58 | if (level === 0 || level > 6) { |
| 59 | return null; |
| 50 | 60 | } |
| 61 | |
| 62 | // Take everything after the hashes, skipping the first character (matches original behavior) |
| 63 | const content = line.substring(level + 1); |
| 64 | const headerTag = `h${level}`; |
| 65 | return wrap(content, headerTag); |
| 51 | 66 | } |
| 52 | 67 | |
| 53 | | function parseLineItem(markdown, list) { |
| 54 | | if (markdown.startsWith('*')) { |
| 55 | | const innerHtml = wrap(parseText(markdown.substring(2), true), 'li'); |
| 56 | | if (list) { |
| 57 | | return [innerHtml, true]; |
| 58 | | } else { |
| 59 | | return [`<ul>${innerHtml}`, true]; |
| 60 | | } |
| 68 | /** |
| 69 | * Parses a list item (* item) to <li> tags |
| 70 | * @param {string} line - Markdown list item |
| 71 | * @returns {string|null} - HTML list item or null if not a list item |
| 72 | */ |
| 73 | function parseListItem(line) { |
| 74 | if (!line.startsWith('* ')) { |
| 75 | return null; |
| 61 | 76 | } |
| 62 | | return [null, list]; |
| 77 | |
| 78 | const content = line.substring(2); |
| 79 | const formattedContent = parseInlineFormatting(content); |
| 80 | return wrap(formattedContent, 'li'); |
| 63 | 81 | } |
| 64 | 82 | |
| 65 | | function parseParagraph(markdown, list) { |
| 66 | | if (!list) { |
| 67 | | return [parseText(markdown, false), false]; |
| 68 | | } else { |
| 69 | | return [`</ul>${parseText(markdown, false)}`, false]; |
| 70 | | } |
| 83 | /** |
| 84 | * Parses a paragraph line to <p> tags |
| 85 | * @param {string} line - Markdown paragraph line |
| 86 | * @returns {string} - HTML paragraph |
| 87 | */ |
| 88 | function parseParagraph(line) { |
| 89 | const formattedContent = parseInlineFormatting(line); |
| 90 | return wrap(formattedContent, 'p'); |
| 71 | 91 | } |
| 72 | 92 | |
| 73 | | function parseLine(markdown, list) { |
| 74 | | let [result, inListAfter] = parseHeader(markdown, list); |
| 75 | | if (result === null) { |
| 76 | | [result, inListAfter] = parseLineItem(markdown, list); |
| 77 | | } |
| 78 | | if (result === null) { |
| 79 | | [result, inListAfter] = parseParagraph(markdown, list); |
| 93 | /** |
| 94 | * Parses a single line of markdown |
| 95 | * @param {string} line - Markdown line |
| 96 | * @returns {Object} - Parsed result with type and content |
| 97 | */ |
| 98 | function parseLine(line) { |
| 99 | // Try to parse as header |
| 100 | const header = parseHeader(line); |
| 101 | if (header !== null) { |
| 102 | return { type: 'header', content: header }; |
| 80 | 103 | } |
| 81 | | if (result === null) { |
| 82 | | throw new Error('Remove this line and implement the function'); |
| 104 | |
| 105 | // Try to parse as list item |
| 106 | const listItem = parseListItem(line); |
| 107 | if (listItem !== null) { |
| 108 | return { type: 'listItem', content: listItem }; |
| 83 | 109 | } |
| 84 | | return [result, inListAfter]; |
| 110 | |
| 111 | // Default to paragraph |
| 112 | return { type: 'paragraph', content: parseParagraph(line) }; |
| 85 | 113 | } |
| 86 | 114 | |
| 87 | 115 | /** |
| 88 | | * @param {string} markdown |
| 89 | | * @returns {string} |
| 116 | * Main markdown parser function |
| 117 | * @param {string} markdown - Markdown text to parse |
| 118 | * @returns {string} - HTML output |
| 90 | 119 | */ |
| 91 | 120 | export function parse(markdown) { |
| 92 | 121 | const lines = markdown.split('\n'); |
| 93 | | let result = ''; |
| 94 | | let list = false; |
| 95 | | for (let i = 0; i < lines.length; i++) { |
| 96 | | let [lineResult, newList] = parseLine(lines[i], list); |
| 97 | | result += lineResult; |
| 98 | | list = newList; |
| 122 | let html = ''; |
| 123 | let inList = false; |
| 124 | |
| 125 | for (const line of lines) { |
| 126 | const parsed = parseLine(line); |
| 127 | |
| 128 | // Handle list opening and closing |
| 129 | if (parsed.type === 'listItem' && !inList) { |
| 130 | // Start a new list |
| 131 | html += '<ul>'; |
| 132 | inList = true; |
| 133 | } else if (parsed.type !== 'listItem' && inList) { |
| 134 | // Close the current list |
| 135 | html += '</ul>'; |
| 136 | inList = false; |
| 137 | } |
| 138 | |
| 139 | // Handle different content types |
| 140 | if (parsed.type === 'header' && inList) { |
| 141 | // Close list before header |
| 142 | html += '</ul>' + parsed.content; |
| 143 | inList = false; |
| 144 | } else { |
| 145 | html += parsed.content; |
| 146 | } |
| 99 | 147 | } |
| 100 | | if (list) { |
| 101 | | return result + '</ul>'; |
| 102 | | } else { |
| 103 | | return result; |
| 148 | |
| 149 | // Close any open list at the end |
| 150 | if (inList) { |
| 151 | html += '</ul>'; |
| 104 | 152 | } |
| 153 | |
| 154 | return html; |
| 105 | 155 | } |