Isomorphic or Universal Javascript

Why I have decided to learn about this?
I first truly took note of the term "Isomorphic JavaScript" when a recruiter sent me through a job which I thought looked extremely interesting. At the time I was not looking for a job, but it reminded me about the long standing problem with decent SEO and Single Page Applications (SPAs). I had heard a lot about React and Angular 2 providing some way to solve the problem, so I was curious.

Notably, the company in question were listing some other design patterns and technologies which were new to me and were also of interest: 12 factor app, Mesos and Marathon, CircleCI.

Godammit man, what does Isomorphic mean!
Isomorphic means "corresponding or similar in form". So essentially we are describing some sort of server side rendering to support the client side application.

Or as the AngularJS Universal Repository puts it: "A JavaScript Application that runs in more environments than just the browser".

The advantages?

• The application does not need to rely on JavaScript being turned on in the browser for it to function
• The application does not need to have a loading gif to explain to the user that patience is required
• THE BIG ONE - The application can be more easily crawled by search engines because the page is also available from a static URL.

Some disadvantages and limitations

• "Uncanny valley" - this is a term used to describe the time between the application appearing to be functioning and available and the time before it is actually responding to the users demands. This can be confusing for the user.
• Loss of separation between back-end and front-end application code. However, I would say, in this API/ Micro-service architecture world, that this actually makes quite a bit of sense. The User Interface will still be separated from Business Logic, we are just blurring the line between server-side "Get" request responses and view rendering.
• This is still just a bootstrapping technique and some SEO issues do still remain.

For a more thorough discussion on why Isomorphic JavaScript is "not the answer" take a look at this discussion on ycombinator (at your own risk of course!).