event baton now working

src/js/util/eventBaton.js

@@ -0,0 +1,63 @@
+var _ = require('underscore');
+
+function EventBaton() {
+  this.eventMap = {};
+}
+
+// this method steals the "baton" -- aka, only this method will now
+// get called. analogous to events.on
+// EventBaton.prototype.on = function(name, func, context) {
+EventBaton.prototype.stealBaton = function(name, func, context) {
+  if (!name) { throw new Error('need name'); }
+
+  var listeners = this.eventMap[name] || [];
+  listeners.push({
+    func: func,
+    context: context
+  });
+  this.eventMap[name] = listeners;
+};
+
+EventBaton.prototype.trigger = function(name) {
+  var argsToApply = [];
+  for (var i = 1; i < arguments.length; i++) {
+    argsToApply.push(arguments[i]);
+  }
+
+  // get the last one
+  var listeners = this.eventMap[name];
+  if (!listeners) {
+    console.warn('no listeners for that event', name);
+    return;
+  }
+  // call the top most listener with context and such
+  var toCall = listeners.slice(-1)[0];
+  toCall.func.apply(toCall.context, argsToApply);
+};
+
+EventBaton.prototype.releaseBaton = function(name, func, context) {
+  if (!name) { throw new Error('need name'); }
+  // might be in the middle of the stack
+  var listeners = this.eventMap[name];
+  if (!listeners || !listeners.length) {
+    throw new Error('no one has that baton!' + name);
+  }
+
+  var newListeners = [];
+  var found = false;
+  _.each(listeners, function(listenerObj) {
+    if (listenerObj.func === func) {
+      found = true;
+    } else {
+      newListeners.push(listenerObj);
+    }
+  }, this);
+
+  if (!found) {
+    throw new Error('did not find that function');
+  }
+  this.eventMap[name] = newListeners;
+};
+
+exports.EventBaton = EventBaton;
+