From fbc4db8da1f8aedd1fb5af25ac31a3e3ae6ee42a Mon Sep 17 00:00:00 2001 From: Dave Smith-Hayes Date: Fri, 23 Aug 2024 20:16:29 -0400 Subject: [PATCH] Add the post about javascript patterns. --- posts/handler-service-presentation.md | 83 --------------------------- posts/more-about-javascript.md | 67 +++++++++++++++++++++ 2 files changed, 67 insertions(+), 83 deletions(-) delete mode 100644 posts/handler-service-presentation.md create mode 100644 posts/more-about-javascript.md diff --git a/posts/handler-service-presentation.md b/posts/handler-service-presentation.md deleted file mode 100644 index a9b1a3e..0000000 --- a/posts/handler-service-presentation.md +++ /dev/null @@ -1,83 +0,0 @@ ---- -title: HS(D)P -description: Describing the architecture of Handlers, Services, (Domains), and Presentation -date: 2024-08-11 -tags: - - development - - javascript - - typescript - - hono -slug: hsdp -draft: true ---- - -## Handlers, Services, (Domains?), Presentation - -In [my last blog post](https://davesmithhayes.com/posts/fullstack-hono) I talked about how I have stopped thinking of my Node.js applications as Model-View-Controller and started thinking of the applications in a new, fun acronym: Handlers, Services, (_sometimes Domains_), and Prfesentation. I thought this would be a good topic for a new blog post. So here it is. - -I am going to be talking about this pattern in relationship to JavaScript and why the language lends itself to the pattern when working on applications. - -## The Application - -Like the previous post, I talked about building this blog with Bun and Hono. I am going to do the same here, however the application we are going to build is the all time classic - The TODO Application. - -## JavaScript - -One of the important things about JavaScript that alluded me for far too long was how the modules actually worked with Node.js. A module before ES6 was simply a JavaScript file that declares a `module.exports` value with the code you want to expose to other modules with the `require` function. Like so: - -```js -function doSomething() { - // ... -} - -module.exports = doSomething; -``` -_`example.js`_ - -Then we can pull in `doSomething` with `require`: - -```js -const doSomething = require('./example'); -``` -_`index.js`_ - -I don't know why I didn't know this, but the code in the `example.js` file is evaluated **and** run during the `require()` call. - -In my past life I would try and build a Singleton class for holding onto an application's Connection Pool to a database. But because of how the Modules in Node.js work, we only need to instantiate the Pool and export it. Here's an example of how we can set up a single pool using the MariaDB official package: - -```js -const mariadb = require('mariadb'); - -const config = { ... }; -const pool = mariadb.createPool(config); - -module.eports = pool; -``` -_`pool.js`_ - -Now the connection pool is only created once and you can require this - - - - - -Outline: - -* Explain what I know about JavaScript -* How does this differ to my experience with PHP -* Describe modules - * Describe how we can set up singletons thinking in modules - * Talk about avoiding classes -* Talk about big express applications - * And how I used to make MVC applications - -Different programming languages require different approaches for organizing code. - - - - - - - - - diff --git a/posts/more-about-javascript.md b/posts/more-about-javascript.md new file mode 100644 index 0000000..78078cb --- /dev/null +++ b/posts/more-about-javascript.md @@ -0,0 +1,67 @@ +--- +title: Thoughts on JavaScript +description: Describing the architecture of Handlers, Services, (Domains), and Presentation +date: 2024-08-11 +tags: + - development + - javascript + - typescript +slug: more-about-javascript +draft: true +--- + +## My History With JavaScript + +I think the first time I wrote JavaScript and got paid for it, I was young, dumb, and willing to work at a design agency for nearly minimum wage making WordPress templates and CakePHP applications. The team I worked with had adopted jQuery for all things front-end - which was the style at the time. I think this time was about 2014. + +From there, I moved on to other Agency jobs and finally ended up at my current place of employment as a lowly _PHP Developer_. This role was designed to solely work on a single Magento 1 codebase. Again, jQuery was the tool of choice. Of course the JavaScript landscape was changing rapidly with the introductions of Node.js, and frameworks like Angular and React. I paid no mind to these since the bulk of my work was still in the world of Magento 1 and working on a plan to migrate to Magento 2. + +It wouldn't be until 2018 (or maybe 2019?) that I would write a line of JavaScript for Node.js. We had decided to go all-in on AWS Lambda. I worked on a service that would push order data out of our Magento instance into our Production Facility's database. Let's call this _The Bridge_. This Lambda was invoked by API Gateway. This was a very small web service, essentially. This was, also, my first experience with _Callback Hell_. There was no `await` and no real `Promise` API (except, _I think_ Bluebird, but I never knew about it at the time) yet. The service actually needed to do a lot of queries, and use those results for other queries, so on, and so forth. If you're familiar with working on Callback Hell you will recognize this: + +```javascript +var mysql = require("mysql"); + +var config = {...}; + +mysql.connect(config, function (err, conn) { + // handle the error + if (err) { + console.error(err); + return; + } + + var query = "INSERT ..."; + + conn.query(query, function (err, results) { + if (err) { + return; + } + + // do something with results + // do another query + conn.query(query, function (err, results) { + // handle error + // do more queries + + conn.query(query, function (err, results) { + // etc. + }); + }); + }); +}); +``` +_This sucks._ + +We ended up rewriting this service in C# as that was the most popular language within the organization at the time. Honestly, thank god. I didn't need to write or maintain the service once it fell into the hands of the .NET team. + +## How I Approached Big Applications + +Eventually all the .NET guys left the company. My boss left the company. I was put in charge and the first thing I did was deploy an Express.js application to completely rewrite the service discussed above. I did this because this was actually faster to do than figure out how the build system (Jenkins, Ansible, and TeamCity _I think_) and deploy it to our common pattern architecture. It was also a way for me to prove to my new boss that I can get things done and that moving to slowly remove our reliance on .NET and IIS for our services was a worthy endeavor. + +A lot of my experience up until that point was mostly working in Magento 2, which is a massive, Enterprisey, PHP application. Modern PHP tends look more and more like C# or Java as the years go on. So that's where my mind is - poisoned by web MVC and Enterprise OOP (_tm_). + + + + + +