So siehts ganz gut aus !

node_modules/es5-ext/string/#/starts-with/shim.js

@@ -0,0 +1,12 @@
+"use strict";
+
+var value     = require("../../../object/valid-value")
+  , toInteger = require("../../../number/to-integer")
+
+  , max = Math.max, min = Math.min;
+
+module.exports = function (searchString/*, position*/) {
+	var start, self = String(value(this));
+	start = min(max(toInteger(arguments[1]), 0), self.length);
+	return self.indexOf(searchString, start) === start;
+};