| 1 | | function wrap(text, tag) { |
| 2 | | return `<${tag}>${text}</${tag}>`; |
| 3 | | } |
| 4 | | |
| 5 | | function isTag(text, tag) { |
| 6 | | return text.startsWith(`<${tag}>`); |
| 7 | | } |
| 1 | /** |
| 2 | * A Markdown parser that converts Markdown syntax to HTML |
| 3 | */ |
| 4 | class MarkdownParser { |
| 5 | constructor() { |
| 6 | this.inList = false; |
| 7 | } |
| 8 | 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 | | } |
| 9 | /** |
| 10 | * Wraps text with HTML tags |
| 11 | * @param {string} text - The text to wrap |
| 12 | * @param {string} tag - The HTML tag to use |
| 13 | * @returns {string} The wrapped text |
| 14 | */ |
| 15 | wrapText(text, tag) { |
| 16 | return `<${tag}>${text}</${tag}>`; |
| 17 | } |
| 14 | 18 | |
| 15 | | function parse__(markdown) { |
| 16 | | return parser(markdown, '__', 'strong'); |
| 17 | | } |
| 19 | /** |
| 20 | * Parses bold text (surrounded by double underscores) |
| 21 | * @param {string} markdown - The markdown text to parse |
| 22 | * @returns {string} The parsed HTML |
| 23 | */ |
| 24 | parseBold(markdown) { |
| 25 | const pattern = new RegExp(`__([^_]+)__`); |
| 26 | const replacement = `<strong>$1</strong>`; |
| 27 | return markdown.replace(pattern, replacement); |
| 28 | } |
| 18 | 29 | |
| 19 | | function parse_(markdown) { |
| 20 | | return parser(markdown, '_', 'em'); |
| 21 | | } |
| 30 | /** |
| 31 | * Parses italic text (surrounded by single underscores) |
| 32 | * @param {string} markdown - The markdown text to parse |
| 33 | * @returns {string} The parsed HTML |
| 34 | */ |
| 35 | parseItalic(markdown) { |
| 36 | const pattern = new RegExp(`_([^_]+)_`); |
| 37 | const replacement = `<em>$1</em>`; |
| 38 | return markdown.replace(pattern, replacement); |
| 39 | } |
| 22 | 40 | |
| 23 | | function parseText(markdown, list) { |
| 24 | | const parsedText = parse_(parse__(markdown)); |
| 25 | | if (list) { |
| 26 | | return parsedText; |
| 27 | | } else { |
| 28 | | return wrap(parsedText, 'p'); |
| 41 | /** |
| 42 | * Parses inline formatting (bold and italic) |
| 43 | * @param {string} markdown - The markdown text to parse |
| 44 | * @returns {string} The parsed HTML |
| 45 | */ |
| 46 | parseInlineFormatting(markdown) { |
| 47 | // Parse bold first, then italic |
| 48 | return this.parseItalic(this.parseBold(markdown)); |
| 29 | 49 | } |
| 30 | | } |
| 31 | 50 | |
| 32 | | function parseHeader(markdown, list) { |
| 33 | | let count = 0; |
| 34 | | for (let i = 0; i < markdown.length; i++) { |
| 35 | | if (markdown[i] === '#') { |
| 36 | | count += 1; |
| 37 | | } else { |
| 38 | | break; |
| 51 | /** |
| 52 | * Parses a header line |
| 53 | * @param {string} line - The line to parse |
| 54 | * @returns {string|null} The parsed HTML or null if not a header |
| 55 | */ |
| 56 | parseHeader(line) { |
| 57 | // Count the number of # at the beginning of the line |
| 58 | const headerMatch = line.match(/^(#{1,6})\s+(.+)$/); |
| 59 | |
| 60 | if (!headerMatch) { |
| 61 | return null; |
| 39 | 62 | } |
| 63 | |
| 64 | const level = headerMatch[1].length; |
| 65 | const content = headerMatch[2]; |
| 66 | const formattedContent = this.parseInlineFormatting(content); |
| 67 | |
| 68 | // Close list if we're in one |
| 69 | const prefix = this.inList ? '</ul>' : ''; |
| 70 | this.inList = false; |
| 71 | |
| 72 | return prefix + this.wrapText(formattedContent, `h${level}`); |
| 40 | 73 | } |
| 41 | | if (count === 0 || count > 6) { |
| 42 | | return [null, list]; |
| 43 | | } |
| 44 | | const headerTag = `h${count}`; |
| 45 | | const headerHtml = wrap(markdown.substring(count + 1), headerTag); |
| 46 | | if (list) { |
| 47 | | return [`</ul>${headerHtml}`, false]; |
| 48 | | } else { |
| 49 | | return [headerHtml, false]; |
| 50 | | } |
| 51 | | } |
| 52 | 74 | |
| 53 | | function parseLineItem(markdown, list) { |
| 54 | | if (markdown.startsWith('*')) { |
| 55 | | const innerHtml = wrap(parseText(markdown.substring(2), true), 'li'); |
| 56 | | if (list) { |
| 57 | | return [innerHtml, true]; |
| 58 | | } else { |
| 59 | | return [`<ul>${innerHtml}`, true]; |
| 75 | /** |
| 76 | * Parses a list item |
| 77 | * @param {string} line - The line to parse |
| 78 | * @returns {string|null} The parsed HTML or null if not a list item |
| 79 | */ |
| 80 | parseListItem(line) { |
| 81 | if (!line.startsWith('* ')) { |
| 82 | return null; |
| 60 | 83 | } |
| 84 | |
| 85 | const content = line.substring(2); |
| 86 | const formattedContent = this.parseInlineFormatting(content); |
| 87 | const listItem = this.wrapText(formattedContent, 'li'); |
| 88 | |
| 89 | // Open list if we're not already in one |
| 90 | const prefix = this.inList ? '' : '<ul>'; |
| 91 | this.inList = true; |
| 92 | |
| 93 | return prefix + listItem; |
| 61 | 94 | } |
| 62 | | return [null, list]; |
| 63 | | } |
| 64 | 95 | |
| 65 | | function parseParagraph(markdown, list) { |
| 66 | | if (!list) { |
| 67 | | return [parseText(markdown, false), false]; |
| 68 | | } else { |
| 69 | | return [`</ul>${parseText(markdown, false)}`, false]; |
| 96 | /** |
| 97 | * Parses a paragraph |
| 98 | * @param {string} line - The line to parse |
| 99 | * @returns {string} The parsed HTML |
| 100 | */ |
| 101 | parseParagraph(line) { |
| 102 | const formattedContent = this.parseInlineFormatting(line); |
| 103 | |
| 104 | // Close list if we're in one |
| 105 | const prefix = this.inList ? '</ul>' : ''; |
| 106 | this.inList = false; |
| 107 | |
| 108 | return prefix + this.wrapText(formattedContent, 'p'); |
| 70 | 109 | } |
| 71 | | } |
| 72 | 110 | |
| 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); |
| 111 | /** |
| 112 | * Parses a single line of markdown |
| 113 | * @param {string} line - The line to parse |
| 114 | * @returns {string} The parsed HTML |
| 115 | */ |
| 116 | parseLine(line) { |
| 117 | // Try to parse as header |
| 118 | const headerResult = this.parseHeader(line); |
| 119 | if (headerResult !== null) { |
| 120 | return headerResult; |
| 121 | } |
| 122 | |
| 123 | // Try to parse as list item |
| 124 | const listItemResult = this.parseListItem(line); |
| 125 | if (listItemResult !== null) { |
| 126 | return listItemResult; |
| 127 | } |
| 128 | |
| 129 | // Parse as paragraph |
| 130 | return this.parseParagraph(line); |
| 80 | 131 | } |
| 81 | | if (result === null) { |
| 82 | | throw new Error('Remove this line and implement the function'); |
| 132 | |
| 133 | /** |
| 134 | * Parses markdown text into HTML |
| 135 | * @param {string} markdown - The markdown text to parse |
| 136 | * @returns {string} The resulting HTML |
| 137 | */ |
| 138 | parse(markdown) { |
| 139 | this.inList = false; |
| 140 | const lines = markdown.split('\n'); |
| 141 | let result = ''; |
| 142 | |
| 143 | for (const line of lines) { |
| 144 | result += this.parseLine(line); |
| 145 | } |
| 146 | |
| 147 | // Close any open list at the end |
| 148 | if (this.inList) { |
| 149 | result += '</ul>'; |
| 150 | } |
| 151 | |
| 152 | return result; |
| 83 | 153 | } |
| 84 | | return [result, inListAfter]; |
| 85 | 154 | } |
| 86 | 155 | |
| 87 | 156 | /** |
| 88 | | * @param {string} markdown |
| 89 | | * @returns {string} |
| 157 | * Parses markdown text into HTML |
| 158 | * @param {string} markdown - The markdown text to parse |
| 159 | * @returns {string} The resulting HTML |
| 90 | 160 | */ |
| 91 | 161 | export function parse(markdown) { |
| 92 | | 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; |
| 99 | | } |
| 100 | | if (list) { |
| 101 | | return result + '</ul>'; |
| 102 | | } else { |
| 103 | | return result; |
| 104 | | } |
| 162 | const parser = new MarkdownParser(); |
| 163 | return parser.parse(markdown); |
| 105 | 164 | } |