Javascript.Net | .Net bindings to the V8 JavaScript engine | Graphics library

I am learning some node.js from Eloquent JavaScript where I found this piece of code whose purpose is to decode the url requested to a server and to resolve it relative to the server’s working directory:

I'm creating an HTML button with JS and I'm defining the onclick function using a element constructing function I wrote/copied from Marijn Haverbeke's Eloquent Javascript

I am creating a button that needs to pass this.id to the onclick function. The onclick function runs, but this.id is coming through in packItem() as undefined.

This method of creating buttons has been working great for me but I can't get the this.id to come through into packItem().

Run code snippet to obtain the undefined id:

I’m picking up Eloquent JavaScript and the answer to this higher-order function exercise has me stumped:

I have a sample Json response as followed below
I know how to filter it using comparison actions like == or >
e.g. I can use $.books[?(@.pages > 460)] to retrieve books with more than 460 pages or
similarly $.books[?(@.pages != 352)] to retrieve books with not 352 pages.
But how can I filter this Json to retrieve books with title containing "Java" substring or published in 2014 year (actually substring too)?
The sample Json is:

I am having a hard time understanding the following class declaration: it seems that element is default to undefined, but I have no idea why

1. is (x, y) in the element = (x,y) => undefined necessary; is (x,y) a abbreviated way of specifying array elements inside element object?
2. use element(x, y) to access array elements inside element?

Says the url is wrong but it seems right to me. I'm trying to download a file from the internet launch the program, then after the process ends to delete the program. Any help would be great

process will be

start exe ---> to create the simple downloader ---> add parameters via bat file ---> launch the file -----> wait for the process to end -----> delete the files downloaded. I have yet to add the wait process and delete commands

I created a Book class which includes a method to add a single object to an array when a button is clicked. But when I click it, what gets added is the button itself from the DOM.

Here is the code:

I simplified the relationships in the model

I write this data as an example. I have two different collections books and publishers