redo ago.js, remove therubyracer gem

Gemfile

@@ -4,7 +4,6 @@ gem 'rails', '4.1.0'
 
 gem 'mysql2'
 gem 'jquery-rails'
-gem 'therubyracer'
 gem 'bcrypt-ruby' # To use ActiveModel's has_secure_password
 gem 'sanitize'
 gem 'redcarpet'

Gemfile.lock

@@ -79,7 +79,6 @@ GEM
       thor (>= 0.14, < 2.0)
     json (1.8.1)
     kgio (2.9.2)
-    libv8 (3.16.14.3)
     mail (2.5.4)
       mime-types (~> 1.16)
       treetop (~> 1.4.8)
@@ -125,7 +124,6 @@ GEM
     rake (10.2.2)
     rb-readline (0.5.1)
     redcarpet (3.1.1)
-    ref (1.0.5)
     rest-client (1.6.7)
       mime-types (>= 1.16)
     ruby-graphviz (1.0.9)
@@ -146,9 +144,6 @@ GEM
       actionpack (>= 3.0)
       activesupport (>= 3.0)
       sprockets (~> 2.8)
-    therubyracer (0.12.1)
-      libv8 (~> 3.16.14.0)
-      ref
     thor (0.19.1)
     thread_safe (0.3.3)
     tilt (1.4.1)
@@ -188,7 +183,6 @@ DEPENDENCIES
   rest-client
   sanitize
   sass-rails
-  therubyracer
   uglifier
   unicorn
   webrick

app/assets/javascripts/ago.js

@@ -1,44 +1,92 @@
-$.fn.ago = function(callback) {
-  units = { // seconds
-    minute:     60,
-    //ocd:     100,
-    hour:     3600,
-    day:     86400,
-    week:   604800,
-    month: 2592000,
-    year: 31536000
+function Ago(nodes, options) {
+  nodes = nodes || document.querySelectorAll("time");
+  options = options || {};
+
+
+  var default_opts = {
+    interval: 10000, // 10 secs
+    units: {
+      minute:     60,
+      hour:     3600,
+      day:     86400,
+      week:   604800,
+      month: 2592000,
+      year: 31536000
+    },
+    date: function(node) {
+      // works on  HTML 'time' nodes
+      return new Date(node.dateTime);
+    },
+    format: "{v} {u} {r}",
+    words: {
+      now: "just now",
+      ago: "ago",
+      ahead: "ahead"
+    },
+    plural: {
+      minute: "minutes",
+      hour: "hours",
+      day: "days",
+      week: "weeks",
+      month: "months",
+      year: "years"
+    }
   };
 
-  this.each(function() {
-    // use the callback or parse time from the node's text
-    ago_date = callback ? callback(this) : new Date($(this).text());
+  // override default options
+  for (var key in default_opts) {
+    options[key] = options[key] || default_opts[key];
+  }
+
+
+  var ago = function(node) {
+    // use callback to get date
+    var ago_date = options.date(node);
     // get seconds ago
     ago_time = (new Date().getTime() - ago_date.getTime()) / 1000;
     ago_time = Math.floor(Math.abs(ago_time));
 
-    // find unit
-    var unit_string = null;
-    var unit_time   = null;
-    for (var unit in units) {
-      var secs = units[unit];
+    // find greatest unit
+    var unit = null;
+    var unit_time = null;
+    for (var u in options.units) {
+      var secs = options.units[u];
       if (ago_time >= secs) {
-        unit_string = unit;
-        unit_time   = secs;
-      } else {
-        // we found the greatest unit
-        break;
+        unit = u;
+        unit_time = secs;
       }
     }
 
-    var ago_str = "just now";
+    var output = null;
     if (unit_time !== null) {
       ago_time = Math.floor(ago_time/unit_time);
-      if (ago_time != 1) unit_string += "s"; // plural
-      ago_str  = ago_time.toString() + " " + unit_string;
+      // plural
+      if (ago_time != 1) unit = options.plural[unit];
       // future or past?
-      ago_str += (ago_time < 0 ? " ahead" : " ago");
+      relative = (ago_time < 0 ? options.words.ahead : options.words.ago);
+
+      output = options.format
+        .replace("{v}", ago_time)
+        .replace("{u}", unit)
+        .replace("{r}", relative);
+    } else {
+      output = options.words.now;
     }
 
-    $(this).text(ago_str);
-  });
-};
+    node.textContent = output;
+  };
+
+
+  var update_all = function() {
+    for (var i = 0; i < nodes.length; i++) {
+      ago(nodes[i]);
+    }
+  };
+
+
+  update_all();
+  setInterval(function() {
+    update_all();
+  }, options.interval);
+
+}

app/assets/javascripts/app.js

@@ -42,12 +42,5 @@ $(function(){
     }
   });
 
-  updateTimestamps();
-  setInterval(updateTimestamps, 1000*10);
-});
-
-function updateTimestamps() {
-  $('time').ago(function(elem){
-    return new Date($(elem).attr('datetime'));
-  });
-}
+  var ago = new Ago();
+});