new sfx and timers

lib/timers.js

@@ -0,0 +1,37 @@
+const util = require('util'),
+  emitter = require('events').EventEmitter;
+
+function Timers()
+{
+    let self = this;
+
+    emitter.call(self);
+
+    self.once = (forTimestamp, eventName) => {
+      // figure out ms between now and scheduled time
+      // setTimeout for event to be fired at that time
+      let diff = forTimestamp - Date.now();
+      if (diff < 0) return;
+      setTimeout(() => {self.emit(eventName)}, diff);
+      return self;
+    };
+
+    self.repeat = (intervalSeconds, eventName) => {
+      setInterval(() => {self.emit(eventName)}, intervalSeconds*1000);
+      return self;
+    };
+
+    self.onceAndRepeat = (forTimestamp, intervalSeconds, eventName) => {
+      let diff = forTimestamp - Date.now();
+      if (diff < 0) return self;
+      setTimeout(() => {
+        self.emit(eventName);
+        self.repeat(intervalSeconds, eventName);
+      }, diff);
+      return self;
+    };
+}
+
+util.inherits(Timers, emitter);
+
+module.exports = new Timers();