I am Joshua Johanan and this is a blog about writing code

Yesterday we finished the post with questions about how to store and use state. All applications have state and have to manage state otherwise they would be static documents. This becomes even more difficult if we try to make our application functional. Functional applications try to minimize state changes as much as possible. How do we do this in a functional application like React? The best way to visualize what functional state looks like is to imagine a series of actions with facts.

We are going to continue our journey into the functional paradigm. In many posts I have made it clear that I like React. Which leads us to the question, why? In the simplest terms, React is functional. It is best utilized when functional ideas are used to design and build components. This forces most programmers to have to think differently. Think in React, as it were. What makes React functional? Functional programming gets its name from Mathematics.

I would say that I am like most programmers, in that I have been trained to program in an imperative way. There is nothing wrong with this. There is another programming paradigm and that is functional. If you have only programmed imperatively, functional programming forces you to reason about your application differently. Functional programming relies on the concepts of immutable data and creating no side effects. I am not making this post to declare a winner between these two.

We will continue in this post covering system related content. Not that long ago it was very difficult to have a development system match a production system. The task of making your local system match any other build was essentially impossible. There were steps you could take, but there was always a small amount of differences. These differences could introduce issues. Those issues would then be very difficult to track down.

Today we will are continuing the topic of system orchestration. When using service discovery you need to be able to register your services for them to be discovered. This is difficult in any case, but even more so with Docker. For the most part I subscribe to the one process per container paradigm. If we need a service registration process that runs along side the container’s main process then that immediately breaks one process per container.

We are going to move away from JavaScript for a few days. The last few months I have been making quite a few posts about Docker, Ansible, and Vagrant. The main reason for this is because I recently moved my blog from a Linux server that was setup by hand to some Docker containers that are automatically configured. In this post I will touch on Consul. Consul is a service discovery tool.

We have seen some ways that we can take advantage of JavaScript’s functional roots. This theme will continue for this post as we will look at call and apply. Call and apply are very similar. Both methods will execute the function, set the this value and pass in parameters. Call does this by having the parameters each explicitly defined while apply takes an array of parameters. Here is an example using our trusty add function and whatIsThis.

We are already at day 3. We are continuing with JavaScript and building on what we have already covered. We are going to cover the bind method of the function object. Bind is used to define what this is inside of a function. It will return a new function (there is that ‘functions are a first class object’ idea again!) and not modify the current function. Let’s look at an example.

This day’s post is a continuation of the last post. In the last post we covered that a function can return a function, but we did not cover any use cases. This post will discuss a very useful one. We have an add function: function add(x, y){ return x + y; } We can partially apply one of the parameters and return a new function. To reinforce what this means we will look at an example.

I am attempting to do something a little different. Right now everywhere you go there is something related to Christmas. This inspired me to challenge myself to write 12 short posts before Christmas. Here is the first. Functions can return functions In JavaScript functions are first class objects. For our purposes here that means that functions can be returned from other functions, used as parameters for other functions, and the value stored in a variable.