You should use `nest` as the this context, rather than `this`. Within the context of [array.map](https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Array/map) or [array.forEach](https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Array/forEach), the this context is the global object (such as the window), unless you specify the optional *thisArg*. Also, typically it would be appropriate to pass the second argument of the index *i* to the function.