Namespaces and Javascript: I Don’t Know What I’m Doing

Here’s a simple JS library I wrote today:

let rr = {};
rr.data = {};
rr.code = {};

rr.code.listen = function (event){
  console.log(this.responseText);
  location.reload();
}

rr.code.remove_request = function () {
  let id_span = document.getElementById("run_id");
  let run_id = id_span.getAttribute("data-run-id");
  console.log([run_id, Date.now()].join("-"))
  let request_id = prompt("Enter the request in Run #" + run_id + " that you want removed");
  if (!(request_id == null || request_id == "")) {
    let url = ["/cgi-bin/dev/dave/env.cgi", run_id, request_id].join("/");
    console.log(url);
    let xhr = new XMLHttpRequest();
    xhr.addEventListener("load",rr.code.listen);
    xhr.open("POST",url);
    xhr.send();
  }
}

// This is part of the *LIMIT TO TEST* aspect of this task.
// I will likely just make this set the onclick
rr.code.start = function () {
  let junk_drawer = document.getElementById("junk_drawer");
  let button = document.createElement('span');
  button.innerText = "Remove Request";
  button.id = "remove_request";
  button.onclick = rr.code.remove_request;
  button.classList.add("button");
  junk_drawer.appendChild(button);
}

window.onload = rr.code.start;

There are a few “conventional” choices – choices made for convention. I put window.onload at the bottom, for example, because in some languages, you get problems if you use a function before you define it. In my language of choice, that matters not, but I am not 100% sure if it matters in JS.

In other places, I have used Bootstrap to make popups that only give the users actual, actionable choices, rather than having them fill a prompt and parsing it, but I figure I will have to parse it on the client end anyway, and this is the quick-and-easy UI choice.

I use let instead of var everywhere and all the time. I think that first let rr puts rr in the global scope, which doesn’t particularly limit anything, but using it everywhere removes the doubt of “should I use it here?”

And then there’s let rr = {}. Could as easily have been let rr = new Object, but that ‘s not the real point. I could have made all the functions function sub () {...} instead of rr.code.sub = function () {...}, but then we may hit issues.

We hit those issues because your libraries are not all that can be running on your page. I just created a web page that was just this –

<!DOCTYPE html>
<html>
</html>

– and Chrome Dev Tools show that content.js and antiphishing.js are running. This and whatever libraries you or your coworkers write or include, and you think you’re the only one who would ever want to write start()?

However, I’m seeing things like document.getElementsByTagNameNS() and suspect there’s a new, cool, somehow more appropriate but unfathomable to me. I cover all sorts of things, and I can have an all-tech staff meeting on my commute in the morning, so if any toes get stepped on with regard to namespaces, it’ll be my shoes doing the stepping.

So, I’m curious: What is the best way to handle JS namespaces? How do you ensure that you don’t break your users toys when throwing more code into a page?

If you have any questions or comments, I would be glad to hear it. Ask me on Twitter or make an issue on my blog repo.

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Namespaces and Javascript: I Don’t Know What I’m Doing

Dave Jacoby

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