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Working on a Local Single Page Application.

Snippets of HTML, CSS, and Javascript in various colors over a solid background.

If only my editor’s highlighter supported template literals.

I’ll surely post about it more detail as I get it fully built, but I thought I’d write about it as I’ve been working on it.

As I’ve written before ( 19 September 2020: “How I Track Games to Buy”) about how I track games to buy, using bookmarks, it occurred to me that I’d like something a little more defined than using bookmark titles to store data. And when I say a little, I mean that. I don’t want a relational database (though there is one built in the browser, if I want to use it). I don’t want a server to configure.

I do want a simple web application, often called a SPASingle-Page Application (Wikipedia: “Single-page application”). But as I said, no server. That makes it an LSPA, or Local Single-Page Application. And single-page really means single file, as in one HTML document that contains all the markup, all the code, and all the styles in one package.

The secret of the modern browser is that it has a ton of functionality that it doesn’t get credit for. While (unfortunately) the behavior of localStorage in the file: schema is undefined, at present Firefox makes it a per-file access, so as long as you persist the filename and path, you get the storage back. To be a little more sure of things, you can export the JSON data as a file, and import it from a file.

I’ve used one-off HTML files for other projects before, including years and years ago for some of my Computer Science classes where choice-of-language was wide-open, but it’s been awhile. In general, the browser is a nice platform to write for, but it’s underdeveloped in terms of making these kind of one-file applications widespread. To be fair, there are concerns about users downloading random HTML files and opening up vulnerabilities, but the general shape of browser security seems to guard decently against it such that enabling more local, serverless, in-browser applications would be useful.

People use spreadsheets for all sorts of data storage and simple applications because it’s got all those tools. They could be doing basically the same thing with a browser. (That’s in fact what I am doing with a browser.) In some cases, the numerical prowess of a spreadsheet will make their task easier. In other cases, the web-awareness of the browser makes my task a lot easier.

One place where a spreadsheets take the one-file ideal slightly further: they store the data in the application. Fair enough.

I looked at various libraries to bootstrap building the editing side of things from a JSON schema. There are a bunch of them, but none seemed very easy to integrate or to do what I wanted with it. It took me less time to build the equivalent for my own purposes than I spent looking at and trying to understand the umpteen JSON-to-forms Javascript libraries. And for mine I don’t add dependencies like underscore.js or jQuery.

On the other hand, I’ve spent a bit of my times dusting my ability to write Javascript, wondering what’s canonical these days. There are proper classes with constructors now (but you don’t have to use them). There are things like Map()s that are better than plain objects in some ways, but aren’t as nice to use in other ways.

To save a file, you have to:

  1. Create an anchor (A).
  2. Create a Blob.
  3. Create an object URL for the Blob.
  4. Add the URL as the anchor’s href attribute.
  5. Add the desired filename as the anchor’s download attribute.
  6. Add the anchor to the document.
  7. Call click() on the anchor (the actual download occurs).
  8. Clean up.

Seems like a lot of extra work for a very usual thing. (A roughly similar process to load from a file, except using an input with type of "file" and some other specifics.)

Anyhow, the one feature I’m relying on an extension for that Bookmarks have out of the box is the ability to get the title and URL in a single action. Mozilla Addons: Hiroaki Nakamura: “Format Link” is an add-on I already use to do that for other cases. But it seems like it’s something browsers should support, given how much we all use the web. We still need computers that understand our most-used forms of data as logical objects, but until then there’s nice extensions to help us.

With that ability, the main pieces of data for tracking a game are available with a paste, which isn’t too much more than simply adding a bookmark. The rest of the data was already stuff I was filling in by hand, but it will soon be into my application rather than cramming it all in the bookmark’s title.

Anything else you’d want from a server-provided service can be built locally and only using Javascript. Given I don’t expect to have hundreds of thousands of games to track, I don’t even need to use a relational database. The browser can handle filtering, sorting, search.

For heavier uses, like media databases, solely relying on a LSPA might not be enough power or might not be able to handle some things like creating thumbnails, but for many other uses, it’s a powerful model that I’d like to see more support and frameworks for people to make use of, especially non-programmers or people with only a little knowledge.

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