Modernize for;;-loops

Change-Id: Ic6f86af0d674cc6643fc9eef2aa7431cfdf514f2
diff --git a/dev/js/src/vc/jsonld.js b/dev/js/src/vc/jsonld.js
index 21260d4..cfa0acc 100644
--- a/dev/js/src/vc/jsonld.js
+++ b/dev/js/src/vc/jsonld.js
@@ -52,8 +52,7 @@
       
       // In case of a group, destroy all operands
       if (this._operands !== undefined) {
-	      for (var i = 0; i < this._operands.length; i++)
-	        this.getOperand(i).destroy();
+        this._operands.forEach(i => i.destroy());
 	      this._operands = [];
       };
     },