From 05dcc77d6432b1995c4574b34c2cccadaa2949fc Mon Sep 17 00:00:00 2001
From: samreid <reids@colorado.edu>
Date: Mon, 6 Nov 2017 20:45:47 -0700
Subject: [PATCH] Moved makeEverythingSlow and makeRandomSlowness to
 initialize-globals, see https://github.com/phetsims/joist/issues/208

---
 js/initialize-globals.js | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/js/initialize-globals.js b/js/initialize-globals.js
index 0b0fa3260..39f95a8b0 100644
--- a/js/initialize-globals.js
+++ b/js/initialize-globals.js
@@ -416,6 +416,30 @@
   // @public (writeable by phet-io) can be overwritten for replicable playback in phet-io.
   window.phet.chipper.randomSeed = phet.chipper.queryParameters.randomSeed;
 
+  /**
+   * Utility function to pause synchronously for the given number of milliseconds.
+   * @param {number} millis - amount of time to pause synchronously
+   */
+  function sleep( millis ) {
+    var date = new Date();
+    var curDate;
+    do {
+      curDate = new Date();
+    } while ( curDate - date < millis );
+  }
+
+  /*
+   * These are used to make sure our sims still behave properly with an artificially higher load (so we can test what happens
+   * at 30fps, 5fps, etc). There tend to be bugs that only happen on less-powerful devices, and these functions facilitate
+   * testing a sim for robustness, and allowing others to reproduce slow-behavior bugs.
+   */
+  window.phet.chipper.makeEverythingSlow = function() {
+    window.setInterval( function() { sleep( 64 ); }, 16 );
+  };
+  window.phet.chipper.makeRandomSlowness = function() {
+    window.setInterval( function() { sleep( Math.ceil( 100 + Math.random() * 200 ) ); }, Math.ceil( 100 + Math.random() * 200 ) );
+  };
+
   /**
    * Enables or disables assertions in common libraries using query parameters.
    * There are two types of assertions: basic and slow. Enabling slow assertions will adversely impact performance.