regex - Convert markdown links from inline to reference

Question

I have a changelog file formatted using Github's markdown.

Initially I used inline links for every link I needed to add, that is:

This is some [example](http://www.stackoverflow.com) line of text.

Over time, as the file grew in size, it became a bit messy due mainly to this way of inserting links.

I'd like to convert all links from inline to reference (see description of each), that is convert the above line to this:

This is some [example][1] line of text.

[1]: http://www.stackoverflow.com

Since the file is rather large and contains many inline links, I was wondering if there is some automated way to do this. I use Sublime Text 3 to edit, but I couldn't find a suitable package for this task. Perhaps some clever regex?

Answer 1

That's a great requirement!

I've just created a new Node.js program (I know it's not a GUI but seems something more people would like the capability of) to do this on GitHub.

Here's also the code:

// node main.js test.md result.md

var fs = require('fs')
fs.readFile(process.argv[2], 'utf8', function (err, markdown) {
    if (err) {
        return console.log(err);
    }
    var counter = 1;
    var matches = {};
    var matcher = /[.*?]((.*?))/g;
    while (match = matcher.exec(markdown)) {
        if (!matches[match[1]]) matches[match[1]] = counter++;
    }
    console.log(matches);
    Object.keys(matches).forEach(function(url) {
        var r = new RegExp("(\[.*?\])\(" + url + "\)", "g");
        markdown = markdown.replace(r, "$1[" + matches[url] + "]");
        markdown += "
[" + matches[url] + "]: " + url;
    });

    fs.writeFile(process.argv[3], markdown, 'utf8', function (err) {
        if (err) return console.log(err);
    });

});