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184 lines
5.8 KiB
JavaScript
184 lines
5.8 KiB
JavaScript
1 year ago
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/*
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* to-markdown - an HTML to Markdown converter
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*
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* Copyright 2011, Dom Christie
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* Licenced under the MIT licence
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*
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*/
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var toMarkdown = function(string) {
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var ELEMENTS = [
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{
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patterns: 'p',
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replacement: function(str, attrs, innerHTML) {
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return innerHTML ? '\n\n' + innerHTML + '\n' : '';
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}
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},
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{
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patterns: 'br',
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type: 'void',
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replacement: '\n'
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},
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{
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patterns: 'h([1-6])',
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replacement: function(str, hLevel, attrs, innerHTML) {
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var hPrefix = '';
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for(var i = 0; i < hLevel; i++) {
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hPrefix += '#';
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}
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return '\n\n' + hPrefix + ' ' + innerHTML + '\n';
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}
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},
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{
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patterns: 'hr',
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type: 'void',
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replacement: '\n\n* * *\n'
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},
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{
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patterns: 'a',
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replacement: function(str, attrs, innerHTML) {
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var href = attrs.match(attrRegExp('href')),
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title = attrs.match(attrRegExp('title'));
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return href ? '[' + innerHTML + ']' + '(' + href[1] + (title && title[1] ? ' "' + title[1] + '"' : '') + ')' : str;
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}
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},
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{
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patterns: ['b', 'strong'],
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replacement: function(str, attrs, innerHTML) {
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return innerHTML ? '**' + innerHTML + '**' : '';
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}
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},
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{
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patterns: ['i', 'em'],
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replacement: function(str, attrs, innerHTML) {
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return innerHTML ? '_' + innerHTML + '_' : '';
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}
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},
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{
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patterns: 'code',
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replacement: function(str, attrs, innerHTML) {
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return innerHTML ? '`' + innerHTML + '`' : '';
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}
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},
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{
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patterns: 'img',
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type: 'void',
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replacement: function(str, attrs, innerHTML) {
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var src = attrs.match(attrRegExp('src')),
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alt = attrs.match(attrRegExp('alt')),
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title = attrs.match(attrRegExp('title'));
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return '![' + (alt && alt[1] ? alt[1] : '') + ']' + '(' + src[1] + (title && title[1] ? ' "' + title[1] + '"' : '') + ')';
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}
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}
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];
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for(var i = 0, len = ELEMENTS.length; i < len; i++) {
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if(typeof ELEMENTS[i].patterns === 'string') {
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string = replaceEls(string, { tag: ELEMENTS[i].patterns, replacement: ELEMENTS[i].replacement, type: ELEMENTS[i].type });
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}
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else {
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for(var j = 0, pLen = ELEMENTS[i].patterns.length; j < pLen; j++) {
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string = replaceEls(string, { tag: ELEMENTS[i].patterns[j], replacement: ELEMENTS[i].replacement, type: ELEMENTS[i].type });
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}
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}
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}
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function replaceEls(html, elProperties) {
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var pattern = elProperties.type === 'void' ? '<' + elProperties.tag + '\\b([^>]*)\\/?>' : '<' + elProperties.tag + '\\b([^>]*)>([\\s\\S]*?)<\\/' + elProperties.tag + '>',
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regex = new RegExp(pattern, 'gi'),
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markdown = '';
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if(typeof elProperties.replacement === 'string') {
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markdown = html.replace(regex, elProperties.replacement);
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}
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else {
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markdown = html.replace(regex, function(str, p1, p2, p3) {
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return elProperties.replacement.call(this, str, p1, p2, p3);
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});
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}
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return markdown;
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}
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function attrRegExp(attr) {
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return new RegExp(attr + '\\s*=\\s*["\']?([^"\']*)["\']?', 'i');
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}
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// Pre code blocks
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string = string.replace(/<pre\b[^>]*>`([\s\S]*)`<\/pre>/gi, function(str, innerHTML) {
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innerHTML = innerHTML.replace(/^\t+/g, ' '); // convert tabs to spaces (you know it makes sense)
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innerHTML = innerHTML.replace(/\n/g, '\n ');
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return '\n\n ' + innerHTML + '\n';
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});
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// Lists
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// Escape numbers that could trigger an ol
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// If there are more than three spaces before the code, it would be in a pre tag
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// Make sure we are escaping the period not matching any character
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string = string.replace(/^(\s{0,3}\d+)\. /g, '$1\\. ');
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// Converts lists that have no child lists (of same type) first, then works it's way up
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var noChildrenRegex = /<(ul|ol)\b[^>]*>(?:(?!<ul|<ol)[\s\S])*?<\/\1>/gi;
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while(string.match(noChildrenRegex)) {
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string = string.replace(noChildrenRegex, function(str) {
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return replaceLists(str);
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});
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}
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function replaceLists(html) {
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html = html.replace(/<(ul|ol)\b[^>]*>([\s\S]*?)<\/\1>/gi, function(str, listType, innerHTML) {
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var lis = innerHTML.split('</li>');
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lis.splice(lis.length - 1, 1);
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for(i = 0, len = lis.length; i < len; i++) {
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if(lis[i]) {
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var prefix = (listType === 'ol') ? (i + 1) + ". " : "* ";
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lis[i] = lis[i].replace(/\s*<li[^>]*>([\s\S]*)/i, function(str, innerHTML) {
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innerHTML = innerHTML.replace(/^\s+/, '');
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innerHTML = innerHTML.replace(/\n\n/g, '\n\n ');
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// indent nested lists
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innerHTML = innerHTML.replace(/\n([ ]*)+(\*|\d+\.) /g, '\n$1 $2 ');
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return prefix + innerHTML;
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});
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}
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}
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return lis.join('\n');
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});
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return '\n\n' + html.replace(/[ \t]+\n|\s+$/g, '');
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}
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// Blockquotes
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var deepest = /<blockquote\b[^>]*>((?:(?!<blockquote)[\s\S])*?)<\/blockquote>/gi;
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while(string.match(deepest)) {
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string = string.replace(deepest, function(str) {
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return replaceBlockquotes(str);
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});
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}
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function replaceBlockquotes(html) {
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html = html.replace(/<blockquote\b[^>]*>([\s\S]*?)<\/blockquote>/gi, function(str, inner) {
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inner = inner.replace(/^\s+|\s+$/g, '');
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inner = cleanUp(inner);
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inner = inner.replace(/^/gm, '> ');
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inner = inner.replace(/^(>([ \t]{2,}>)+)/gm, '> >');
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return inner;
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});
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return html;
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}
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function cleanUp(string) {
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string = string.replace(/^[\t\r\n]+|[\t\r\n]+$/g, ''); // trim leading/trailing whitespace
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string = string.replace(/\n\s+\n/g, '\n\n');
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string = string.replace(/\n{3,}/g, '\n\n'); // limit consecutive linebreaks to 2
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return string;
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}
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return cleanUp(string);
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};
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if (typeof exports === 'object') {
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exports.toMarkdown = toMarkdown;
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}
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