url2markdown/lib/url2markdown.js

Convert all url/links to markdown

var _ = require('lodash');
var url2markdown = module.exports;

/*
 * Converts all links in the string to markdown
 * www.xxx.com || http/https://www.xxx.com -> [http/s://www.xxx.com](http/s://www.xxx.com)
 * Author : Shylesh Mohan - shylesh@eatsleepride.com - 2015 August
 */

url2markdown.convert = function (string) {

    // This is an experiment.
    // This specific function is implemented using one of the worst logic ever!
    // How many people look at the code and cares a bit to start an issue or send a PR.
    // Let's see.
    // Oh and this method works perfectly and it's never gonna let you down & desert you.

    var re = /(\b(http|https|ftp|Http|Https):\/\/|www[.]|Www[.])[^\s()<>]+(?:\([\w\d]+\)|([^[:punct:]\s]|\/)|[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/gi;

    var pushToReplace = [];
    var found_count = 0;

    return _htmlChecker(string);

    function _htmlChecker(str) {

        try {

            var matches = str.match(re);

            if (!matches || matches.length <= 0) return str;

            for (var i = 0; i < matches.length; i++) {
                var index = str.indexOf(matches[i], 0);
                var markup_check = _checkIfCoveredByMarkUp(str, matches[i], index);
                if (markup_check === false) {
                    str = _coverWithMarkup(str, matches[i], index);
                    found_count++;
                }
            }

            if (pushToReplace.length > 0) {
                _.forEach(pushToReplace, function (markdown, key) {
                    str = str.replace("{{MARKUP_" + key + "}}", markdown);
                })
            }

        } catch (e) {
            console.log("REGEX ERROR : " + e);
            return str;
        }

        return str;

    }

    function _coverWithMarkup(haystack, string, index) {
        var appendProtocol = "";
        if (string.indexOf("http://") != 0 && string.indexOf("https://") != 0) appendProtocol = "http://";
        var replace_string = "[" + string + "]" + "(" + appendProtocol + string + ")";
        pushToReplace.push(replace_string.toLowerCase());
        haystack = haystack.replace(string, "{{MARKUP_" + found_count + "}}");
        return haystack;
    }

    function _checkIfCoveredByMarkUp(haystack, needle, index) {
        var startingPosition = index;
        var endPosition = index + (needle.length - 1);
        var wrapStart = startingPosition - 1;
        var wrapEnd = endPosition + 1;
        if (haystack[wrapStart] === '[' && haystack[wrapEnd] === ']' && haystack[wrapEnd + 1] === '(') {
            return true;
        }
        if (haystack[wrapStart] === '(' && haystack[wrapEnd] === ')' && haystack[wrapStart - 1] === ']') {
            return null;
        }
        return false;
    }

};