async function readFile(path, callback) {

    function reading() {

        fs.readFile(path, 'utf8', function(err, rawData) {

            if (err) {

                console.error(err);
                return;

            }else{

                if(callback) {

                    callback(rawData);

                }

            }

        });

    }


    if(fs.existsSync(path)) {

        reading();

    }else{

        console.error('File does not exist: ' + path);

    }

}

function loadDataFromFile(path, callback) {

    var rawData, parsedData;

    async function parseData(rawData) {

        return new Promise((resolve, reject) => {

            parsedData = JSON.parse(rawData);

            if(callback) {

                callback(parsedData);

            }

            resolve();


        });

    }

    return readFile(path, parseData);

}

const findClosest = (arr, num) => {
   const creds = arr.reduce((acc, val, ind) => {
      let { diff, index } = acc;
      const difference = Math.abs(val["A"] - num);
      if(difference < diff){
         diff = difference;
         index = ind;
      };
      return { diff, index };
   }, {
      diff: Infinity,
      index: -1
   });
   return arr[creds.index];
};

var makeObjective = function(targetFunc,xlist,ylist) {
  var objective = function(params) {
    var total = 0.0;
    for(var i=0; i < xlist.length; ++i) {
      var resultThisDatum = targetFunc(params, xlist[i]);
      var delta = resultThisDatum - ylist[i];
      total += (delta*delta);
    }
    return total;
  };
  return objective;
};

var cubic = function(params,x) {
  return params[0] * x*x*x +
    params[1] * x*x +
    params[2] * x +
    params[3];
};

var linear = function(params, x) {
    return params[0]*x + params[1];
};

function SquareFitter() {

    this.count = 0;
    this.sumX = 0;
    this.sumX2 = 0;
    this.sumX3 = 0;
    this.sumX4 = 0;
    this.sumY = 0;
    this.sumXY = 0;
    this.sumX2Y = 0;

}

SquareFitter.prototype = {

    'add': function(x, y) {

        this.count++;
        this.sumX += x;
        this.sumX2 += x*x;
        this.sumX3 += x*x*x;
        this.sumX4 += x*x*x*x;
        this.sumY += y;
        this.sumXY += x*y;
        this.sumX2Y += x*x*y;

    },
    'project': function(x) {

        var det = this.count*this.sumX2*this.sumX4 - this.count*this.sumX3*this.sumX3 - this.sumX*this.sumX*this.sumX4 + 2*this.sumX*this.sumX2*this.sumX3 - this.sumX2*this.sumX2*this.sumX2;
        var offset = this.sumX*this.sumX2Y*this.sumX3 - this.sumX*this.sumX4*this.sumXY - this.sumX2*this.sumX2*this.sumX2Y + this.sumX2*this.sumX3*this.sumXY + this.sumX2*this.sumX4*this.sumY - this.sumX3*this.sumX3*this.sumY;
        var scale = -this.count*this.sumX2Y*this.sumX3 + this.count*this.sumX4*this.sumXY + this.sumX*this.sumX2*this.sumX2Y - this.sumX*this.sumX4*this.sumY - this.sumX2*this.sumX2*this.sumXY + this.sumX2*this.sumX3*this.sumY;
        var accel = this.sumY*this.sumX*this.sumX3 - this.sumY*this.sumX2*this.sumX2 - this.sumXY*this.count*this.sumX3 + this.sumXY*this.sumX2*this.sumX - this.sumX2Y*this.sumX*this.sumX + this.sumX2Y*this.count*this.sumX2;

        return (offset + x*scale + x*x*accel) / det;

    }

};

function squareProject(data) {

    var fitter = new SquareFitter();

    for(var i = 0; i < data.length; i++) {

    	console.log(i, data[i]);
        fitter.add(i, data[i]);

    }

    return fitter;

}

var getDateFromDayNum = function(dayNum, year){

    var date = new Date();

    if(year) {
        date.setFullYear(year);
    }

    date.setMonth(0);
    date.setDate(0);

    var timeOfFirst = date.getTime(); // this is the time in milliseconds of 1/1/YYYY
    var dayMilli = 1000 * 60 * 60 * 24;
    var dayNumMilli = dayNum * dayMilli;

    date.setTime(timeOfFirst + dayNumMilli);

    return date;

}

function degToRad(degrees) {

	let pi = Math.PI;

	return degrees * (pi / 180);

}

function radToDeg(radians) {

	var pi = Math.PI;

	return radians * (180 / pi);

}

function getTextWidth(text, font) {
	
    // re-use canvas object for better performance

    text = text.replace("&sup", "");
    text = text.replace("&#183", "");
    var canvas = getTextWidth.canvas || (getTextWidth.canvas = document.createElement("canvas"));
    var context = canvas.getContext("2d");
    context.font = font;
    var metrics = context.measureText(text);

    return metrics.width;

}

function daysInMonth(month, year) {

    return new Date(year, month, 0).getDate();

}

function colorLuminance(color, luminosity) {

	// validate hex string
	color = new String(color).replace(/[^0-9a-f]/gi, '');
	if (color.length < 6) {
		color = color[0]+ color[0]+ color[1]+ color[1]+ color[2]+ color[2];
	}
	luminosity = luminosity || 0;

	// convert to decimal and change luminosity
	var newColor = "#", c, i, black = 0, white = 255;
	for (i = 0; i < 3; i++) {
		c = parseInt(color.substr(i*2,2), 16);
		c = Math.round(Math.min(Math.max(black, c + (luminosity * white)), white)).toString(16);
		newColor += ("00"+c).substr(c.length);
	}
	return newColor; 

	/*if (color.length >6) { color= color.substring(1,color.length)}
    var rgb = parseInt(color, 16); 
    var r = Math.abs(((rgb >> 16) & 0xFF)+v); if (r>255) r=r-(r-255);
    var g = Math.abs(((rgb >> 8) & 0xFF)+v); if (g>255) g=g-(g-255);
    var b = Math.abs((rgb & 0xFF)+v); if (b>255) b=b-(b-255);
    r = Number(r < 0 || isNaN(r)) ? 0 : ((r > 255) ? 255 : r).toString(16); 
    if (r.length == 1) r = '0' + r;
    g = Number(g < 0 || isNaN(g)) ? 0 : ((g > 255) ? 255 : g).toString(16); 
    if (g.length == 1) g = '0' + g;
    b = Number(b < 0 || isNaN(b)) ? 0 : ((b > 255) ? 255 : b).toString(16); 
    if (b.length == 1) b = '0' + b;
    return "#" + r + g + b;*/

	/*
	// validate hex string
	hex = String(hex).replace(/[^0-9a-f]/gi, '');
	if (hex.length < 6) {
		hex = hex[0]+hex[0]+hex[1]+hex[1]+hex[2]+hex[2];
	}
	lum = lum || 0;

	// convert to decimal and change luminosity
	var rgb = "#", c, i;
	for (i = 0; i < 3; i++) {
		c = parseInt(hex.substr(i*2,2), 16);
		c = Math.round(Math.min(Math.max(0, c + (c * lum)), 255)).toString(16);
		rgb += ("00"+c).substr(c.length);
	}

	return rgb;
	*/

}

function parseHTML(html) {

	var t = document.createElement('template');
	t.innerHTML = html;

	return t.content.cloneNode(true);

}

function parseSVG(svg) {

	var parser = new DOMParser();
	var doc = parser.parseFromString(svg, "image/svg+xml");

	return doc;

}