Markdown parser, done right. 100% CommonMark support, extensions, syntax plugins & high speed https://markdown-it.github.io/
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(function () {
'use strict';
/*eslint-env browser*/
/*global $, _*/
var mdHtml, mdSrc, permalink, scrollMap;
var defaults = {
html: false, // Enable HTML tags in source
xhtmlOut: false, // Use '/' to close single tags (<br />)
breaks: false, // Convert '\n' in paragraphs into <br>
langPrefix: 'language-', // CSS language prefix for fenced blocks
linkify: true, // autoconvert URL-like texts to links
typographer: true, // Enable smartypants and other sweet transforms
// options below are for demo only
_highlight: true,
_strict: false,
_view: 'html' // html / src / debug
};
defaults.highlight = function (str, lang) {
if (!defaults._highlight || !window.hljs) { return ''; }
var hljs = window.hljs;
if (lang && hljs.getLanguage(lang)) {
try {
return hljs.highlight(lang, str).value;
} catch (__) {}
}
try {
return hljs.highlightAuto(str).value;
} catch (__) {}
return '';
};
function setOptionClass(name, val) {
if (val) {
$('body').addClass('opt_' + name);
} else {
$('body').removeClass('opt_' + name);
}
}
function setResultView(val) {
$('body').removeClass('result-as-html');
$('body').removeClass('result-as-src');
$('body').removeClass('result-as-debug');
$('body').addClass('result-as-' + val);
defaults._view = val;
}
function mdInit() {
if (defaults._strict) {
mdHtml = window.markdownit('commonmark');
mdSrc = window.markdownit('commonmark');
} else {
mdHtml = window.markdownit('full', defaults)
.use(window.markdownitEmoji);
mdSrc = window.markdownit('full', defaults)
.use(window.markdownitEmoji);
}
// Beautify output of parser for html content
mdHtml.renderer.rules.table_open = function () {
return '<table class="table table-striped">\n';
};
// Replace emoji codes with images
mdHtml.renderer.rules.emoji = function(token, idx) {
return window.twemoji.parse(token[idx].to);
};
//
// Inject line numbers for sync scroll. Notes:
//
// - We track only headings and paragraphs on first level. That's enougth.
// - Footnotes content causes jumps. Level limit filter it automatically.
//
mdHtml.renderer.rules.paragraph_open = function (tokens, idx) {
var line;
if (tokens[idx].lines && tokens[idx].level === 0) {
line = tokens[idx].lines[0];
return '<p class="line" data-line="' + line + '">';
}
return '<p>';
};
mdHtml.renderer.rules.heading_open = function (tokens, idx) {
var line;
if (tokens[idx].lines && tokens[idx].level === 0) {
line = tokens[idx].lines[0];
return '<h' + tokens[idx].hLevel + ' class="line" data-line="' + line + '">';
}
return '<h' + tokens[idx].hLevel + '>';
};
}
function setHighlightedlContent(selector, content, lang) {
if (window.hljs) {
$(selector).html(window.hljs.highlight(lang, content).value);
} else {
$(selector).text(content);
}
}
function updateResult() {
var source = $('.source').val();
// Update only active view to avoid slowdowns
// (debug & src view with highlighting are a bit slow)
if (defaults._view === 'src') {
setHighlightedlContent('.result-src-content', mdSrc.render(source), 'html');
} else if (defaults._view === 'debug') {
setHighlightedlContent(
'.result-debug-content',
JSON.stringify(mdSrc.parse(source, { references: {} }), null, 2),
'json'
);
} else { /*defaults._view === 'html'*/
$('.result-html').html(mdHtml.render(source));
}
// reset lines mapping cache on content update
scrollMap = null;
try {
if (source) {
// serialize state - source and options
permalink.href = '#md64=' + window.btoa(JSON.stringify({
source: source,
defaults: _.omit(defaults, 'highlight')
}));
} else {
permalink.href = '';
}
} catch (__) {
permalink.href = '';
}
}
// Build offsets for each line (lines can be wrapped)
// That's a bit dirty to process each line everytime, but ok for demo.
// Optimizations are required only for big texts.
function buildScrollMap() {
var i, offset, nonEmptyList, pos, a, b, lineHeightMap, linesCount,
acc, sourceLikeDiv, textarea = $('.source'),
_scrollMap;
sourceLikeDiv = $('<div />').css({
position: 'absolute',
visibility: 'hidden',
height: 'auto',
width: textarea[0].clientWidth,
'font-size': textarea.css('font-size'),
'font-family': textarea.css('font-family'),
'line-height': textarea.css('line-height'),
'white-space': textarea.css('white-space')
}).appendTo('body');
offset = $('.result-html').scrollTop() - $('.result-html').offset().top;
_scrollMap = [];
nonEmptyList = [];
lineHeightMap = [];
acc = 0;
textarea.val().split('\n').forEach(function(str) {
var h, lh;
lineHeightMap.push(acc);
if (str.length === 0) {
acc++;
return;
}
sourceLikeDiv.text(str);
h = parseFloat(sourceLikeDiv.css('height'));
lh = parseFloat(sourceLikeDiv.css('line-height'));
acc += Math.round(h / lh);
});
sourceLikeDiv.remove();
lineHeightMap.push(acc);
linesCount = acc;
for (i = 0; i < linesCount; i++) { _scrollMap.push(-1); }
nonEmptyList.push(0);
_scrollMap[0] = 0;
$('.line').each(function(n, el) {
var $el = $(el), t = $el.data('line');
if (t === '') { return; }
t = lineHeightMap[t];
if (t !== 0) { nonEmptyList.push(t); }
_scrollMap[t] = Math.round($el.offset().top + offset);
});
nonEmptyList.push(linesCount);
_scrollMap[linesCount] = $('.result-html')[0].scrollHeight;
pos = 0;
for (i = 1; i < linesCount; i++) {
if (_scrollMap[i] !== -1) {
pos++;
continue;
}
a = nonEmptyList[pos];
b = nonEmptyList[pos + 1];
_scrollMap[i] = Math.round((_scrollMap[b] * (i - a) + _scrollMap[a] * (b - i)) / (b - a));
}
return _scrollMap;
}
function syncScroll() {
var textarea = $('.source'),
lineHeight = parseFloat(textarea.css('line-height')),
lineNo, posTo;
lineNo = Math.floor(textarea.scrollTop() / lineHeight);
if (!scrollMap) { scrollMap = buildScrollMap(); }
posTo = scrollMap[lineNo];
$('.result-html').stop(true).animate({
scrollTop: posTo
}, 100, 'linear');
}
//////////////////////////////////////////////////////////////////////////////
// Init on page load
//
$(function() {
// highlight snippet
if (window.hljs) {
$('pre.code-sample code').each(function(i, block) {
window.hljs.highlightBlock(block);
});
}
// Restore content if opened by permalink
if (location.hash && /^(#md=|#md64=)/.test(location.hash)) {
try {
var cfg;
if (/^#md64=/.test(location.hash)) {
cfg = JSON.parse(window.atob(location.hash.slice(6)));
} else {
// Legacy mode for old links. Those become broken in github posts,
// so we switched to base64 encoding.
cfg = JSON.parse(decodeURIComponent(location.hash.slice(4)));
}
if (_.isString(cfg.source)) {
$('.source').val(cfg.source);
}
var opts = _.isObject(cfg.defaults) ? cfg.defaults : {};
// copy config to defaults, but only if key exists
// and value has the same type
_.forOwn(opts, function (val, key) {
if (!_.has(defaults, key)) { return; }
// Legacy, for old links
if (key === '_src') {
defaults._view = val ? 'src' : 'html';
return;
}
if ((_.isBoolean(defaults[key]) && _.isBoolean(val)) ||
(_.isString(defaults[key]) && _.isString(val))) {
defaults[key] = val;
}
});
// sanitize for sure
if ([ 'html', 'src', 'debug' ].indexOf(defaults._view) === -1) {
defaults._view = 'html';
}
} catch (__) {}
}
// Activate tooltips
$('._tip').tooltip({ container: 'body' });
// Set default option values and option listeners
_.forOwn(defaults, function (val, key) {
if (key === 'highlight') { return; }
var el = document.getElementById(key);
if (!el) { return; }
var $el = $(el);
if (_.isBoolean(val)) {
$el.prop('checked', val);
$el.on('change', function () {
var value = Boolean($el.prop('checked'));
setOptionClass(key, value);
defaults[key] = value;
mdInit();
updateResult();
});
setOptionClass(key, val);
} else {
$(el).val(val);
$el.on('change update keyup', function () {
defaults[key] = String($(el).val());
mdInit();
updateResult();
});
}
});
setResultView(defaults._view);
mdInit();
permalink = document.getElementById('permalink');
// Setup listeners
$('.source').on('keyup paste cut mouseup', _.debounce(updateResult, 300, { maxWait: 500 }));
$('.source').on('scroll', _.debounce(syncScroll, 50, { maxWait: 50 }));
$('.source-clear').on('click', function (event) {
$('.source').val('');
updateResult();
event.preventDefault();
});
$(document).on('click', '[data-result-as]', function (event) {
var view = $(this).data('resultAs');
if (view) {
setResultView(view);
// only to update permalink
updateResult();
event.preventDefault();
}
});
// Need to recalculate line positions on window resize
$(window).on('resize', function () {
scrollMap = null;
});
updateResult();
});
})();