如何在PageDown.js中将rel =“nofollow”属性添加到外部链接？

Question

I'm using PageDown.js to make raw HTML in markdown style like StackOverflow does. My code looks like the following in nodejs:

var saneConv require('./pagedown/Markdown.Sanitizer'),
    resultHTML = saneConv.makeHtml('[raw html string]');

Now I need to add rel="nofollow" to all external links. Unfortunately I can't see that ability in PageDown itself.

Could you advice me please a solution to add ref="nofollow" attribute to all external links?

Answer 1

If all links are external then you could simply use

resultHTML = resultHTML.replace('<a ', '<a rel="nofollow" ');

or there's a function called writeAnchorTag in Markdown.Converter.js that you can change to do what you need.

Update

var jsdom = require("jsdom");
var fs = require("fs");
var jquery = fs.readFileSync("./path/to/jquery.js", "utf-8");

var saneConv = require('./pagedown/Markdown.Sanitizer'),
    resultHTML = saneConv.makeHtml('[raw html string]');

jsdom.env(resultHTML, [jquery], function(err, window) {
    var $ = window.$;

    $("a").each(function() {
        var $a = $(this);
        var href = $a.attr('href');

        // figure out if href is external or internal
        // let's say if href doesn't contain specific domain it's external so add rel=nofollow
        if (href.indexOf('example.com') < 0 || href.indexOf('example2.com') < 0) {
            // it's external, let's add rel=nofollow
            $a.attr('rel', 'nofollow');
        }
    });
});