"use strict";
var Promise = require('bluebird'),
md = require('markdown-it'),
mdEmoji = require('markdown-it-emoji'),
mdTaskLists = require('markdown-it-task-lists'),
mdAbbr = require('markdown-it-abbr'),
mdAnchor = require('markdown-it-anchor'),
mdFootnote = require('markdown-it-footnote'),
mdExternalLinks = require('markdown-it-external-links'),
mdExpandTabs = require('markdown-it-expand-tabs'),
mdAttrs = require('markdown-it-attrs'),
hljs = require('highlight.js'),
cheerio = require('cheerio'),
_ = require('lodash'),
mdRemove = require('remove-markdown');
// Load plugins
var mkdown = md({
html: true,
linkify: true,
typography: true,
highlight(str, lang) {
if (lang && hljs.getLanguage(lang)) {
try {
return '<pre class="hljs"><code>' + hljs.highlight(lang, str, true).value + '</code></pre>';
} catch (err) {
return '<pre><code>' + str + '</code></pre>';
}
}
return '<pre><code>' + str + '</code></pre>';
}
})
.use(mdEmoji)
.use(mdTaskLists)
.use(mdAbbr)
.use(mdAnchor, {
slugify: _.kebabCase,
permalink: true,
permalinkClass: 'toc-anchor',
permalinkSymbol: '#',
permalinkBefore: true
})
.use(mdFootnote)
.use(mdExternalLinks, {
externalClassName: 'external-link',
internalClassName: 'internal-link'
})
.use(mdExpandTabs, {
tabWidth: 4
})
.use(mdAttrs);
// Rendering rules
mkdown.renderer.rules.emoji = function(token, idx) {
return '<i class="twa twa-' + _.replace(token[idx].markup, /_/g, '-') + '"></i>';
};
/**
* Parse markdown content and build TOC tree
*
* @param {(Function|string)} content Markdown content
* @return {Array} TOC tree
*/
const parseTree = (content) => {
let tokens = md().parse(content, {});
let tocArray = [];
//-> Extract headings and their respective levels
for (let i = 0; i < tokens.length; i++) {
if (tokens[i].type !== "heading_close") {
continue;
}
const heading = tokens[i - 1];
const heading_close = tokens[i];
if (heading.type === "inline") {
let content = "";
let anchor = "";
if (heading.children && heading.children[0].type === "link_open") {
content = heading.children[1].content;
anchor = _.kebabCase(content);
} else {
content = heading.content;
anchor = _.kebabCase(heading.children.reduce((acc, t) => acc + t.content, ""));
}
tocArray.push({
content,
anchor,
level: +heading_close.tag.substr(1, 1)
});
}
}
//-> Exclude levels deeper than 2
_.remove(tocArray, (n) => { return n.level > 2; });
//-> Build tree from flat array
return _.reduce(tocArray, (tree, v) => {
let treeLength = tree.length - 1;
if(v.level < 2) {
tree.push({
content: v.content,
anchor: v.anchor,
nodes: []
});
} else {
let lastNodeLevel = 1;
let GetNodePath = (startPos) => {
lastNodeLevel++;
if(_.isEmpty(startPos)) {
startPos = 'nodes';
}
if(lastNodeLevel === v.level) {
return startPos;
} else {
return GetNodePath(startPos + '[' + (_.at(tree[treeLength], startPos).length - 1) + '].nodes');
}
};
let lastNodePath = GetNodePath();
let lastNode = _.get(tree[treeLength], lastNodePath);
if(lastNode) {
lastNode.push({
content: v.content,
anchor: v.anchor,
nodes: []
});
_.set(tree[treeLength], lastNodePath, lastNode);
}
}
return tree;
}, []);
};
/**
* Parse markdown content to HTML
*
* @param {String} content Markdown content
* @return {String} HTML formatted content
*/
const parseContent = (content) => {
let output = mkdown.render(content);
let cr = cheerio.load(output);
//-> Check for empty first element
let firstElm = cr.root().children().first()[0];
if(firstElm.type === 'tag' && firstElm.name === 'p') {
let firstElmChildren = firstElm.children;
if(firstElmChildren.length < 1) {
firstElm.remove();
} else if(firstElmChildren.length === 1 && firstElmChildren[0].type === 'tag' && firstElmChildren[0].name === 'img') {
cr(firstElm).addClass('is-gapless');
}
}
//-> Remove links in headers
cr('h1 > a:not(.toc-anchor), h2 > a:not(.toc-anchor), h3 > a:not(.toc-anchor)').each((i, elm) => {
let txtLink = cr(elm).text();
cr(elm).replaceWith(txtLink);
});
//-> Re-attach blockquote styling classes to their parents
cr.root().children('blockquote').each((i, elm) => {
if(cr(elm).children().length > 0) {
let bqLastChild = cr(elm).children().last()[0];
let bqLastChildClasses = cr(bqLastChild).attr('class');
if(bqLastChildClasses && bqLastChildClasses.length > 0) {
cr(bqLastChild).removeAttr('class');
cr(elm).addClass(bqLastChildClasses);
}
}
});
//-> Enclose content below headers
cr('h2').each((i, elm) => {
let subH2Content = cr(elm).nextUntil('h1, h2');
cr(elm).after('<div class="indent-h2"></div>');
let subH2Container = cr(elm).next('.indent-h2');
_.forEach(subH2Content, (ch) => {
cr(subH2Container).append(ch);
});
});
cr('h3').each((i, elm) => {
let subH3Content = cr(elm).nextUntil('h1, h2, h3');
cr(elm).after('<div class="indent-h3"></div>');
let subH3Container = cr(elm).next('.indent-h3');
_.forEach(subH3Content, (ch) => {
cr(subH3Container).append(ch);
});
});
output = cr.html();
return output;
};
/**
* Parse meta-data tags from content
*
* @param {String} content Markdown content
* @return {Object} Properties found in the content and their values
*/
const parseMeta = (content) => {
let commentMeta = new RegExp('<!-- ?([a-zA-Z]+):(.*)-->','g');
let results = {}, match;
while(match = commentMeta.exec(content)) {
results[_.toLower(match[1])] = _.trim(match[2]);
}
return results;
};
module.exports = {
/**
* Parse content and return all data
*
* @param {String} content Markdown-formatted content
* @return {Object} Object containing meta, html and tree data
*/
parse(content) {
return {
meta: parseMeta(content),
html: parseContent(content),
tree: parseTree(content)
};
},
parseContent,
parseMeta,
parseTree,
/**
* Strips non-text elements from Markdown content
*
* @param {String} content Markdown-formatted content
* @return {String} Text-only version
*/
removeMarkdown(content) {
return mdRemove(_.chain(content)
.replace(/<!-- ?([a-zA-Z]+):(.*)-->/g, '')
.replace(/```[^`]+```/g, '')
.replace(/`[^`]+`/g, '')
.replace(new RegExp('(?!mailto:)(?:(?:http|https|ftp)://)(?:\\S+(?::\\S*)?@)?(?:(?:(?:[1-9]\\d?|1\\d\\d|2[01]\\d|22[0-3])(?:\\.(?:1?\\d{1,2}|2[0-4]\\d|25[0-5])){2}(?:\\.(?:[0-9]\\d?|1\\d\\d|2[0-4]\\d|25[0-4]))|(?:(?:[a-z\\u00a1-\\uffff0-9]+-?)*[a-z\\u00a1-\\uffff0-9]+)(?:\\.(?:[a-z\\u00a1-\\uffff0-9]+-?)*[a-z\\u00a1-\\uffff0-9]+)*(?:\\.(?:[a-z\\u00a1-\\uffff]{2,})))|localhost)(?::\\d{2,5})?(?:(/|\\?|#)[^\\s]*)?', 'g'), '')
.replace(/\r?\n|\r/g, ' ')
.deburr()
.toLower()
.replace(/(\b([^a-z]+)\b)/g, ' ')
.replace(/[^a-z]+/g, ' ')
.replace(/(\b(\w{1,2})\b(\W|$))/g, '')
.replace(/\s\s+/g, ' ')
.value()
);
}
};