diff --git a/lib/js/test/test-double-rendering.js b/lib/js/test/test-double-rendering.js
index 5d9cd2a..b4b79b8 100644
--- a/lib/js/test/test-double-rendering.js
+++ b/lib/js/test/test-double-rendering.js
@@ -46,7 +46,7 @@
  */
 
 // double assertion threshold
-var EPSILON = 0.0000001;
+const EPSILON = 0.0000001;
 
 // Work around for old API used by QUnitAdapter of jsTestDriver
 if (typeof QUnit.log == 'function') {
@@ -67,17 +67,17 @@
 
   QUnit.test('Double (rendering)', function(assert) {
     console.log('Double rendering test -- starts');
-    var EXPECTED_DOUBLE_ASSIGNED_TO_INT_CONSTANT = 1;
-    var EXPECTED_DOUBLE_ASSIGNED_TO_NEGATIVE_INT_CONSTANT = -100;
-    var EXPECTED_DOUBLE_ASSIGNED_TO_LARGEST_INT_CONSTANT = 9223372036854775807;
-    var EXPECTED_DOUBLE_ASSIGNED_TO_SMALLEST_INT_CONSTANT = -9223372036854775807;
-    var EXPECTED_DOUBLE_ASSIGNED_TO_DOUBLE_WITH_MANY_DECIMALS = 3.14159265359;
-    var EXPECTED_DOUBLE_ASSIGNED_TO_FRACTIONAL_DOUBLE = 1000000.1;
-    var EXPECTED_DOUBLE_ASSIGNED_TO_NEGATIVE_FRACTIONAL_DOUBLE = -1000000.1;
-    var EXPECTED_DOUBLE_ASSIGNED_TO_LARGE_DOUBLE = 1.7e+308;
-    var EXPECTED_DOUBLE_ASSIGNED_TO_LARGE_FRACTIONAL_DOUBLE = 9223372036854775816.43;
-    var EXPECTED_DOUBLE_ASSIGNED_TO_SMALL_DOUBLE = -1.7e+308;
-    var EXPECTED_DOUBLE_ASSIGNED_TO_NEGATIVE_BUT_LARGE_FRACTIONAL_DOUBLE = -9223372036854775816.43;
+    const EXPECTED_DOUBLE_ASSIGNED_TO_INT_CONSTANT = 1;
+    const EXPECTED_DOUBLE_ASSIGNED_TO_NEGATIVE_INT_CONSTANT = -100;
+    const EXPECTED_DOUBLE_ASSIGNED_TO_LARGEST_INT_CONSTANT = 9223372036854775807;
+    const EXPECTED_DOUBLE_ASSIGNED_TO_SMALLEST_INT_CONSTANT = -9223372036854775807;
+    const EXPECTED_DOUBLE_ASSIGNED_TO_DOUBLE_WITH_MANY_DECIMALS = 3.14159265359;
+    const EXPECTED_DOUBLE_ASSIGNED_TO_FRACTIONAL_DOUBLE = 1000000.1;
+    const EXPECTED_DOUBLE_ASSIGNED_TO_NEGATIVE_FRACTIONAL_DOUBLE = -1000000.1;
+    const EXPECTED_DOUBLE_ASSIGNED_TO_LARGE_DOUBLE = 1.7e+308;
+    const EXPECTED_DOUBLE_ASSIGNED_TO_LARGE_FRACTIONAL_DOUBLE = 9223372036854775816.43;
+    const EXPECTED_DOUBLE_ASSIGNED_TO_SMALL_DOUBLE = -1.7e+308;
+    const EXPECTED_DOUBLE_ASSIGNED_TO_NEGATIVE_BUT_LARGE_FRACTIONAL_DOUBLE = -9223372036854775816.43;
     assert.ok(
         Math.abs(EXPECTED_DOUBLE_ASSIGNED_TO_INT_CONSTANT - DOUBLE_ASSIGNED_TO_INT_CONSTANT_TEST) <= EPSILON);
     assert.ok(
@@ -131,11 +131,11 @@
     assert.equal(typeof DOUBLE_ASSIGNED_TO_LARGE_FRACTIONAL_DOUBLE_TEST, 'number');
     assert.equal(typeof DOUBLE_ASSIGNED_TO_SMALL_DOUBLE_TEST, 'number');
     assert.equal(typeof DOUBLE_ASSIGNED_TO_NEGATIVE_BUT_LARGE_FRACTIONAL_DOUBLE_TEST, 'number');
-    var EXPECTED_DOUBLE_LIST =
+    const EXPECTED_DOUBLE_LIST =
         [1,-100,100,9223372036854775807,-9223372036854775807,3.14159265359,1000000.1,-1000000.1,1.7e+308,-1.7e+308,
             9223372036854775816.43,-9223372036854775816.43];
     assert.equal(DOUBLE_LIST_TEST.length, EXPECTED_DOUBLE_LIST.length);
-    for (var i = 0; i < EXPECTED_DOUBLE_LIST.length; ++i) {
+    for (let i = 0; i < EXPECTED_DOUBLE_LIST.length; ++i) {
            assert.ok(Math.abs(EXPECTED_DOUBLE_LIST[i] - DOUBLE_LIST_TEST[i]) <= EPSILON);
     }
     console.log('Double rendering test -- ends');