Colorizing GitHub pull requests by age

github-colorizer.js

// ==UserScript==
// @name         GitHub Pull Request Colorizer
// @namespace    http://github.com/UlfS
// @version      0.1
// @description  Colorizes the pull requests depending on age (green=new, red=older than 10 days)
// @author       UlfS
// @match        https://github.com/*pulls*
// include      /https?://github.com/([^/]+/[^/]+/)?pulls(&.*)?/
// @grant        none
// ==/UserScript==

var colorHueRange   = [0.32, 0];
var colorSaturation = 1;
var colorLightness  = 0.9;
var hourRange       = [0, 24*10];

// hslToRgb taken from https://gist.github.com/mjackson/5311256
/**
 * Converts an HSL color value to RGB. Conversion formula
 * adapted from http://en.wikipedia.org/wiki/HSL_color_space.
 * Assumes h, s, and l are contained in the set [0, 1] and
 * returns r, g, and b in the set [0, 255].
 *
 * @param   Number  h       The hue
 * @param   Number  s       The saturation
 * @param   Number  l       The lightness
 * @return  Array           The RGB representation
 */
function hslToRgb(h, s, l) {
  var r, g, b;

  if (s == 0) {
    r = g = b = l; // achromatic
  } else {
    function hue2rgb(p, q, t) {
      if (t < 0) t += 1;
      if (t > 1) t -= 1;
      if (t < 1/6) return p + (q - p) * 6 * t;
      if (t < 1/2) return q;
      if (t < 2/3) return p + (q - p) * (2/3 - t) * 6;
      return p;
    }

    var q = l < 0.5 ? l * (1 + s) : l + s - l * s;
    var p = 2 * l - q;

    r = hue2rgb(p, q, h + 1/3);
    g = hue2rgb(p, q, h);
    b = hue2rgb(p, q, h - 1/3);
  }

  return [ r * 255, g * 255, b * 255 ];
}

function pad2(s) {
  return s.length < 2 ? '0'+s : s;
}

function toColorCode(x) {
    return '#'+ x.map(function(num) {return pad2(Math.round(num).toString(16));}).join("");
}

function norm(fromRange, toRange, value) {
    return (toRange[1]-toRange[0])/(fromRange[1]-fromRange[0])*(Math.min(value, fromRange[1])-fromRange[1])+toRange[1];
}

var divs = document.getElementsByClassName('Box-row');
for (var i=0, div; div = divs[i]; i++) {
    var date = Date.parse(div.getElementsByTagName("relative-time")[0].getAttribute("datetime"));
    var hoursAgo = Math.abs(Date.now() - date) / (60*60*1000);
    var colorH = norm(hourRange, colorHueRange, hoursAgo);
    var color = toColorCode(hslToRgb(colorH, colorSaturation, colorLightness));
    div.style.backgroundColor=color;
}