prism-line-highlight.js
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(function(){
if (typeof self === 'undefined' || !self.Prism || !self.document || !document.querySelector) {
return;
}
function $$(expr, con) {
return Array.prototype.slice.call((con || document).querySelectorAll(expr));
}
function hasClass(element, className) {
className = " " + className + " ";
return (" " + element.className + " ").replace(/[\n\t]/g, " ").indexOf(className) > -1
}
// Some browsers round the line-height, others don't.
// We need to test for it to position the elements properly.
var isLineHeightRounded = (function() {
var res;
return function() {
if(typeof res === 'undefined') {
var d = document.createElement('div');
d.style.fontSize = '13px';
d.style.lineHeight = '1.5';
d.style.padding = 0;
d.style.border = 0;
d.innerHTML = ' <br /> ';
document.body.appendChild(d);
// Browsers that round the line-height should have offsetHeight === 38
// The others should have 39.
res = d.offsetHeight === 38;
document.body.removeChild(d);
}
return res;
}
}());
function highlightLines(pre, lines, classes) {
var ranges = lines.replace(/\s+/g, '').split(','),
offset = +pre.getAttribute('data-line-offset') || 0;
var parseMethod = isLineHeightRounded() ? parseInt : parseFloat;
var lineHeight = parseMethod(getComputedStyle(pre).lineHeight);
for (var i=0, range; range = ranges[i++];) {
range = range.split('-');
var start = +range[0],
end = +range[1] || start;
var line = document.createElement('div');
line.textContent = Array(end - start + 2).join(' \n');
line.className = (classes || '') + ' line-highlight';
//if the line-numbers plugin is enabled, then there is no reason for this plugin to display the line numbers
if(!hasClass(pre, 'line-numbers')) {
line.setAttribute('data-start', start);
if(end > start) {
line.setAttribute('data-end', end);
}
}
line.style.top = (start - offset - 1) * lineHeight + 'px';
//allow this to play nicely with the line-numbers plugin
if(hasClass(pre, 'line-numbers')) {
//need to attack to pre as when line-numbers is enabled, the code tag is relatively which screws up the positioning
pre.appendChild(line);
} else {
(pre.querySelector('code') || pre).appendChild(line);
}
}
}
function applyHash() {
var hash = location.hash.slice(1);
// Remove pre-existing temporary lines
$$('.temporary.line-highlight').forEach(function (line) {
line.parentNode.removeChild(line);
});
var range = (hash.match(/\.([\d,-]+)$/) || [,''])[1];
if (!range || document.getElementById(hash)) {
return;
}
var id = hash.slice(0, hash.lastIndexOf('.')),
pre = document.getElementById(id);
if (!pre) {
return;
}
if (!pre.hasAttribute('data-line')) {
pre.setAttribute('data-line', '');
}
highlightLines(pre, range, 'temporary ');
document.querySelector('.temporary.line-highlight').scrollIntoView();
}
var fakeTimer = 0; // Hack to limit the number of times applyHash() runs
Prism.hooks.add('complete', function(env) {
var pre = env.element.parentNode;
var lines = pre && pre.getAttribute('data-line');
if (!pre || !lines || !/pre/i.test(pre.nodeName)) {
return;
}
clearTimeout(fakeTimer);
$$('.line-highlight', pre).forEach(function (line) {
line.parentNode.removeChild(line);
});
highlightLines(pre, lines);
fakeTimer = setTimeout(applyHash, 1);
});
addEventListener('hashchange', applyHash);
})();