index.js

var request = require('request'),
    cheerio = require('cheerio');


/**
 * List of contributons, latest commit, streak etc.
 *
 * @param  {string} url - URL to the github repo
 * @param  {function} callback - Receives the data
 */
exports.scrapeContributionDataAndStats = function(url, callback) {
    var returnObj = {};
    getRequest(url, function(html) {
        scrapeContributionData(html, function(contributionData) {
            returnObj = formatReturnData(contributionData, deriveContributionStats(contributionData));
            callback(returnObj);
        });
    });
};


/**
 * Derive the streak
 *
 * @param  {object} contributionData - Contribution data
 * @return {object} - Stats derived from the contribution data
 */
function deriveContributionStats(contributionData) {

    // Some variables
    var longestStreak = 0;
    var currentStreak = 0;
    var lastDay = '0-0-0';

    // Reduce the total number of contributions to a single integer
    const totalContributions = contributionData.reduce(function (last, current, index) {

        // Calculate the exptected day to continue the streak
        var expectedDay = new Date(lastDay);
        expectedDay.setDate(expectedDay.getDate() + 1); // Increment day by 1

        const year = expectedDay.getFullYear();
        var month = expectedDay.getMonth() + 1; // The month starts from zero
        var day = expectedDay.getDate();

        // Left-pad for noobs
        if (month < 10) { month = '0' + month; }
        if (day < 10) { day = '0' + day; }

        expectedDay = (
            year + '-' +
            month + '-' +
            day
        );

        // If the streak was continued, increment, else reset
        if (expectedDay === current.dataDate) {
            currentStreak++;
        } else {
            currentStreak = 0;
        }

        if (currentStreak > longestStreak) {
            longestStreak = currentStreak;
        }

        // Update the last day
        lastDay = current.dataDate;

        return last + current.dataContributionCount;
    }, 0);

    return {
        totalContributions: totalContributions,
        longestStreak: longestStreak + 1,
        currentStreak: currentStreak + 1
    };
}


/**
 * Neatly formats contributionData and statsData
 *
 * @param  {object} contributionData
 * @param  {object} statsData
 * @return {object} - Returns null if no commits have happened today
 */
function formatReturnData(contributionData, statsData) {
    var commitsToday = getCommitsToday(contributionData);
    var returnData = {contributionData: contributionData, statsData: statsData, commitsToday: commitsToday};
    return commitsToday == null ? null : returnData;
};


/**
 * Returns the amount of contributions that happened on the current day
 *
 * @param  {object} contributionData
 * @return {integer} - Amount of contributions in the current day
 */
function getCommitsToday(contributionData) {
    if (!contributionData) {
        return null;
    }

    // Grab latest commit data
    var latestCommits = contributionData[contributionData.length - 1];
    var latestCommitsDate = dayOfYear(latestCommits.dataDate);
    var today = new Date();
    var todaysDate = dayOfYear(today.getFullYear()+'-'+(today.getMonth()+1)+'-'+today.getDate());

    // Check if the lastest commit data is from today or not
    if (latestCommitsDate === todaysDate) {
        return latestCommits.dataContributionCount;
    }

    return 0;
};

/**
 * Returns an object containing contribution data
 *
 * @param  {string} html - HTML of the github page
 * @param  {function} callback - Receives contribution data
 */
function scrapeContributionData(html, callback) {
    $ = cheerio.load(html);
    var commitDataArray = [];

    $('rect').each(function(index, commitData) {
        // Look for our contribtion data
        var dataContributionCount = parseInt(commitData.attribs['data-count']),
            dataDate = commitData.attribs['data-date'],
            commitDataObj = {};

        // Validate it contains data
        if (dataContributionCount && dataDate) {
            commitDataObj.dataContributionCount = dataContributionCount;
            commitDataObj.dataDate = dataDate;
            commitDataArray.push(commitDataObj);
        }
    });

    // Validate it contains data before sending
    if (commitDataArray.length > 0) {
        callback(commitDataArray);
    } else {
        // If it fails validation return null
        callback(null);
    }
};


/**
 * Opiniated get request
 *
 * @param  {string} gitUrl
 * @param  {function} callback3
 */
function getRequest(gitUrl, callback) {
    var options = {
        url: gitUrl
    };
    request.get(options, function(error, response, body) {
        if(!error) {
            callback(body);
        }
        return error;
    });
};


/**
 * Returns the day of the year
 *
 * @param {string, date} date - Can be a string or a timestamp
 * @return {integer} The day of the year
 */
function dayOfYear(date) {
    var now = new Date(date);
    var start = new Date(now.getFullYear(), 0, 0);
    var diff = now - start;
    var oneDay = 1000 * 60 * 60 * 24;
    var day = Math.floor(diff / oneDay);

    return day;
}

// Deprecated warnings
exports.scrapeContributionData = function() {
    console.log('Deprecation warning: scrapeContributionData has been deprecated in favor of just using scrapeContributionDataAndStats.');
};
exports.scrapeContributionStats = function() {
    console.log('Deprecation warning: scrapeContributionData has been deprecated in favor of just using scrapeContributionDataAndStats.');
};