joplin/packages/lib/markdownUtils.ts

import { validateLinks } from '@joplin/renderer';
const stringPadding = require('string-padding');
const urlUtils = require('./urlUtils');
import type * as MarkdownItType from 'markdown-it';
import MarkdownIt from 'markdown-it';

// Taken from codemirror/addon/edit/continuelist.js
const listRegex = /^(\s*)([*+-] \[[x ]\]\s|[*+-]\s|(\d+)([.)]\s))(\s*)/;
const emptyListRegex = /^(\s*)([*+-] \[[x ]\]|[*+-]|(\d+)[.)])(\s+)$/;

export enum MarkdownTableJustify {
	Left = 'left',
	Center = 'center',
	Right = 'right',
}

export interface MarkdownTableHeader {
	name: string;
	label: string;
	labelUrl?: string;
	filter?: (content: string)=> string;
	disableEscape?: boolean;
	disableHtmlEscape?: boolean;
	justify?: MarkdownTableJustify;
}

export interface MarkdownTableRow {
	[key: string]: string;
}

export interface MarkdownTable {
	header: MarkdownTableHeader[];
	rows: MarkdownTableRow[];
}

const markdownUtils = {
	// Titles for markdown links only need escaping for [ and ]
	escapeTitleText(text: string) {
		return text.replace(/(\[|\])/g, '\\$1');
	},

	escapeLinkUrl(url: string) {
		url = url.replace(/\(/g, '%28');
		url = url.replace(/\)/g, '%29');
		url = url.replace(/ /g, '%20');
		return url;
	},

	escapeTableCell(text: string, escapeHtml = true) {
		// Disable HTML code
		if (escapeHtml) {
			text = text.replace(/</g, '&lt;');
			text = text.replace(/>/g, '&gt;');
		}
		// Table cells can't contain new lines so replace with <br/>
		text = text.replace(/\n/g, '<br/>');
		// "|" is a reserved characters that should be escaped
		text = text.replace(/\|/g, '\\|');
		return text;
	},

	escapeInlineCode(text: string): string {
		// https://github.com/github/markup/issues/363#issuecomment-55499909
		return text.replace(/`/g, '``');
	},

	unescapeLinkUrl(url: string) {
		url = url.replace(/%28/g, '(');
		url = url.replace(/%29/g, ')');
		url = url.replace(/%20/g, ' ');
		return url;
	},

	prependBaseUrl(md: string, baseUrl: string) {
		// eslint-disable-next-line no-useless-escape -- Old code before rule was applied
		return md.replace(/(\]\()([^\s\)]+)(.*?\))/g, (_match: string, before: string, url: string, after: string) => {
			return before + urlUtils.prependBaseUrl(url, baseUrl) + after;
		});
	},

	// Returns the **encoded** URLs, so to be useful they should be decoded again before use.
	extractFileUrls(md: string, onlyType: string = null): string[] {
		const markdownIt = new MarkdownIt();
		markdownIt.validateLink = validateLinks; // Necessary to support file:/// links

		const env = {};
		const tokens = markdownIt.parse(md, env);
		const output: string[] = [];

		let linkType = onlyType;
		if (linkType === 'pdf') linkType = 'link_open';

		const searchUrls = (tokens: MarkdownItType.Token[]) => {
			for (let i = 0; i < tokens.length; i++) {
				const token = tokens[i];
				if ((!onlyType && (token.type === 'link_open' || token.type === 'image')) || (!!onlyType && token.type === onlyType) || (onlyType === 'pdf' && token.type === 'link_open')) {
					// Pdf embeds are a special case, they are represented as 'link_open' tokens but are marked with 'embedded_pdf' as link name by the parser
					// We are making sure if its in the proper pdf link format, only then we add it to the list
					if (onlyType === 'pdf' && !(tokens.length > i + 1 && tokens[i + 1].type === 'text' && tokens[i + 1].content === 'embedded_pdf')) continue;
					for (let j = 0; j < token.attrs.length; j++) {
						const a = token.attrs[j];
						if ((a[0] === 'src' || a[0] === 'href') && a.length >= 2 && a[1]) {
							output.push(a[1]);
						}
					}
				}

				if (token.children && token.children.length) {
					searchUrls(token.children);
				}
			}
		};

		searchUrls(tokens);

		return output;
	},

	replaceResourceUrl(md: string, urlToReplace: string, id: string) {
		const linkRegex = `(?<=\\]\\()\\<?${urlToReplace}\\>?(?=.*\\))`;
		const reg = new RegExp(linkRegex, 'g');
		return md.replace(reg, `:/${id}`);
	},

	extractImageUrls(md: string) {
		return markdownUtils.extractFileUrls(md, 'image');
	},

	extractPdfUrls(md: string) {
		return markdownUtils.extractFileUrls(md, 'pdf');
	},

	// The match results has 5 items
	// Full match array is
	// [Full match, whitespace, list token, ol line number, whitespace following token]
	olLineNumber(line: string) {
		const match = line.match(listRegex);
		return match ? Number(match[3]) : 0;
	},

	extractListToken(line: string) {
		const match = line.match(listRegex);
		return match ? match[2] : '';
	},

	isListItem(line: string) {
		return listRegex.test(line);
	},

	isEmptyListItem(line: string) {
		return emptyListRegex.test(line);
	},

	createMarkdownTable(headers: MarkdownTableHeader[], rows: MarkdownTableRow[]): string {
		const output = [];

		const minCellWidth = 5;

		const headersMd = [];
		const lineMd = [];
		for (let i = 0; i < headers.length; i++) {
			const h = headers[i];
			let label = h.label;
			if (h.labelUrl) {
				label = `[${h.label}](${h.labelUrl})`;
			}
			headersMd.push(stringPadding(label, minCellWidth, ' ', stringPadding.RIGHT));

			const justify = h.justify ? h.justify : MarkdownTableJustify.Left;

			if (justify === MarkdownTableJustify.Left) {
				lineMd.push('-----');
			} else if (justify === MarkdownTableJustify.Center) {
				lineMd.push(':---:');
			} else {
				lineMd.push('----:');
			}
		}

		output.push(`| ${headersMd.join(' | ')} |`);
		output.push(`| ${lineMd.join(' | ')} |`);

		for (let i = 0; i < rows.length; i++) {
			const row = rows[i];
			const rowMd = [];
			for (let j = 0; j < headers.length; j++) {
				const h = headers[j];
				const value = (h.filter ? h.filter(row[h.name]) : row[h.name]) || '';
				const valueMd = h.disableEscape ? value : markdownUtils.escapeTableCell(value, !h.disableHtmlEscape);
				rowMd.push(stringPadding(valueMd, minCellWidth, ' ', stringPadding.RIGHT));
			}
			output.push(`| ${rowMd.join(' | ')} |`);
		}

		return output.join('\n');
	},

	countTableColumns(line: string) {
		if (!line) return 0;

		const trimmed = line.trim();
		let pipes = (line.match(/\|/g) || []).length;

		if (trimmed[0] === '|') { pipes -= 1; }
		if (trimmed[trimmed.length - 1] === '|') { pipes -= 1; }

		return pipes + 1;
	},

	matchingTableDivider(header: string, divider: string) {
		if (!header || !divider) return false;

		const invalidChars = divider.match(/[^\s\-:|]/g);

		if (invalidChars) { return false; }

		const columns = markdownUtils.countTableColumns(header);
		const cols = markdownUtils.countTableColumns(divider);
		return cols > 0 && (cols >= columns);
	},

	titleFromBody(body: string) {
		if (!body) return '';
		const spaceEntities = /&nbsp;/g;
		body = body.replace(spaceEntities, ' ');
		const lines = body.split('\n');
		let title = '';

		for (const line of lines) {
			const trimmed = line.trim();
			if (trimmed) {
				title = trimmed;
				break;
			}
		}

		title = title.replace(/<\/?(ins|del|mark|sub|sup)>/g, '');
		title = title.replace(/!?\[([^\]]*)\]\(([^()\n]+(?:\([^()\n]*\)[^()\n]*)*)\)/g, (_match, text, url) => {
			return text || url;
		});
		const formattingPatterns = [
			/(\*\*\*|___)(.*?)\1/g,
			/(\*\*|__)(.*?)\1/g,
			/(\*|_)(.*?)\1/g,
			/(~~)(.*?)\1/g,
			/(==)(.*?)\1/g,
			/(\^)(.*?)\1/g,
		];

		let prev;
		do {
			prev = title;
			for (const pattern of formattingPatterns) {
				title = title.replace(pattern, '$2');
			}
		} while (title !== prev);

		title = title.replace(/^\s*([-*+]|\d+[.)])\s+(\[[ xX]\]\s+)?/, '');
		title = title.replace(/^(~{2,}|={2,})$/, '');
		title = title.replace(/^[#>\-*`\s=]+/, '');
		title = title.replace(/[#>\-*`\s=]+$/, '');
		title = title.trim();
		return title.substring(0, 80);
	},
};

export default markdownUtils;