From 5f1acf3c66d9e128883a7a54409a08a42ab9ea05 Mon Sep 17 00:00:00 2001
From: Stephen Blott
Date: Fri, 18 Mar 2016 06:12:55 +0000
Subject: Add Utils.makeIdempotent.

The intention is to use this to clean up some of the initialisation
sequences in the front end.
---
 lib/utils.coffee | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'lib')

diff --git a/lib/utils.coffee b/lib/utils.coffee
index 9969811a..31f4bec6 100644
--- a/lib/utils.coffee
+++ b/lib/utils.coffee
@@ -236,6 +236,10 @@ Utils =
   # Like Nodejs's nextTick.
   nextTick: (func) -> @setTimeout 0, func
 
+  # Make an idempotent function.
+  makeIdempotent: (func) ->
+    (args...) -> ([previousFunc, func] = [func, null])[0]? args...
+
 # Utility for parsing and using the custom search-engine configuration.  We re-use the previous parse if the
 # search-engine configuration is unchanged.
 SearchEngines =
-- 
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