In a great demonstration of why we need regression tests, and why you should use hasOwnProperty in a loop, my polyfill for includes seriously broke codelens.

bnmnetp · bnmnetp · commit 07202a420a76 · 2015-07-20T15:11:30.000-05:00
diff --git a/runestone/codelens/js/codelens.js b/runestone/codelens/js/codelens.js
@@ -31,9 +31,11 @@ function attachLoggers(codelens, divid) {
 }
 
 function redrawAllVisualizerArrows() {
+    var i;
     if (allVisualizers !== undefined) {
-        for (var v in allVisualizers)
-            allVisualizers[v].redrawConnectors();
+        for (i = 0; i < allVisualizers.length; i++) {
+            allVisualizers[i].redrawConnectors();
+        }
     }
 }
 function styleButtons(divid) {

Original file line number	Diff line number	Diff line change
`@@ -31,9 +31,11 @@ function attachLoggers(codelens, divid) {`
`31`	`31`	`}`
`32`	`32`
`33`	`33`	`function redrawAllVisualizerArrows() {`
	`34`	`+ var i;`
`34`	`35`	`if (allVisualizers !== undefined) {`
`35`		`- for (var v in allVisualizers)`
`36`		`- allVisualizers[v].redrawConnectors();`
	`36`	`+ for (i = 0; i < allVisualizers.length; i++) {`
	`37`	`+ allVisualizers[i].redrawConnectors();`
	`38`	`+ }`
`37`	`39`	`}`
`38`	`40`	`}`
`39`	`41`	`function styleButtons(divid) {`