Izmjenjena struktura, dodan backand

web/node_modules/core-js/modules/es6.array.find-index.js

@@ -0,0 +1,14 @@
+'use strict';
+// 22.1.3.9 Array.prototype.findIndex(predicate, thisArg = undefined)
+var $export = require('./$.export')
+  , $find   = require('./$.array-methods')(6)
+  , KEY     = 'findIndex'
+  , forced  = true;
+// Shouldn't skip holes
+if(KEY in [])Array(1)[KEY](function(){ forced = false; });
+$export($export.P + $export.F * forced, 'Array', {
+  findIndex: function findIndex(callbackfn/*, that = undefined */){
+    return $find(this, callbackfn, arguments.length > 1 ? arguments[1] : undefined);
+  }
+});
+require('./$.add-to-unscopables')(KEY);