introduce signal, start using in history; use consts for signal name

introduces two new modules:
scripts/consts.js
scripts/signal.js

signal is a thin wrapper for jquery('window').on and
jquery('window').trigger, which seems like an adaquete signal library -
there are faster things around, but why introduce another dependency.

1 files changed, 22 insertions, 0 deletions

diff --git a/scripts/signal.js b/scripts/signal.js
new file mode 100644
index 00000000..49c5afd3
--- /dev/null
+++ b/scripts/signal.js
@@ -0,0 +1,22 @@
+/*
+ * Signal/slot (i.e. blackboard pattern) for rhizi.
+ *
+ * This is a thin wrapper over jquery right now.
+ * But just keeping it here to make any future change of implementation slightly
+ * easier.
+ */
+
+define('signal', ['jquery'], function($) {
+    function slot(name, handler) {
+        $(window).on(name, function(e, args) {
+            handler(args);
+        });
+    };
+    function signal(name, obj) {
+        $(window).trigger(name, obj);
+    }
+    return {
+        'slot': slot,
+        'signal': signal
+    };
+})