ES2015 (ES6) or Typescript


I get the question,  “Karl, why do you use ES2015 (ES6)?”

The answer I give depends on the context of the question, in other words what is the scenario we are asking about.

I will answer the question for each of these scenarios:

  • Authoring JavaScript Framework
  • Authoring Large Line of Business Application with more than a few developers
  • Authoring a small application with one or a few developers

Authoring JavaScript Framework

Without equivocation I would use Typescript for a JavaScript Framework.

Why, because I can transpile to ES2015 or ES5, so I can deliver my framework in Typescript, ES2015, or ES5.

Several years from now, I’ll be able to transpile my framework to ES vNext (as long as Typescript is still around and maintained properly), effectively future proofing my code.

I don’t have the hassle of 3rd party .d.ts files that are old or incomplete because my framework probably does not have many 3rd party dependencies.

If my framework does have them, I have the resources to create the required .d.ts files.  I’ll pay this tax because the benefits outweigh the .d.ts file hassles.

Authoring Large Line of Business Application with More Than a Few Developers

Without equivocation I would use Typescript for building a large line of business application with more than a few developers.

Why, because I can leverage the compile time checking, strong typing, and interfaces that Typescript offers; additionally I would use a linter with very strict rules.

I say this for several reasons.  First, because in a large team project like this, you need to reign in some developers so that they don’t get off the path of sensible and maintainable Typescript (JavaScript).  I care much more about creating a maintainable product than I do about someone’s feelings or creative coding desires.  The very strict linter rules also help developers sharpen their JavaScript coding skills.

Second, because Typescript does perform strong type checking at compile time.

Back all this up with unit and integration tests, and you have the basis for a very successful large line of business application.

Authoring a Small Application with One or a Few Developers

Here is where my answer to the original question changes from Typescript to ES2015.

For all of my personnel projects and blog post projects, I’ll use ES2015 (ES6).

For small team projects, I would still like to use ES2015.


  • Because I write simple ES2015 JavaScript that looks like C#
  • Because I write very clean ES2015 that is very easy to read
  • Because I use a ES6 linter with very strict rules, helps keep my ES6 clean and I’ve learned a lot from the linter rules I violated
  • Because I don’t want to pay the 15% tax for authoring Typescript (adding the type definitions to the code,  getting the .d.ts files downloaded, and imported in the code.  This 15% does not count towards missing or incorrect .d.ts files.)
  • Because I don’t want to deal with 3rd party .d.ts files that are either out of date or missing – this can be a real bummer
  • Because I like the dynamic nature of JavaScript and leverage that capability on occasion
  • Because for a long time, basically a single developer was managing the Definitely Typed github repro.  I look at it yesterday and it seems to have gotten a face lift and many new developers helping out.
  • Because the tool Microsoft ships for creating .d.ts files does not render a .d.ts file that can be used, I always found myself having to add more code to them to get them to work.
  • Just because you’re using a framework that was authored in Typescript, it does not mean you have to use Typescript.

Obviously, these are my opinions, and I know that others can easily come back with solutions or comments, but after many projects using Typescript this what I’ve decided to do.

I don’t want to give the impression that there is a huge gap between perfect .d.ts files and the few that I had trouble with.  But those few I needed, well, I needed them.  It got old dealing with this problem.  Remember, demo ware does not have this problem.  Its when you’re developing real applications that need libraries for services and features, and those services and features have missing, or outdated .d.ts files.  This is where the bummer begins.  I think if Microsoft delivered a tool that I could point to a JavaScript library and it would render a .d.ts file that could be used in the project, I may back off on this gripe.  But I have tried to make the missing .d.ts files and spent precious time messing with this.

All developers need to evaluate languages, tools, frameworks, and 3rd party dependencies for all of their projects, and pick the ones that meet the needs of that specific project.

Select the best tool for the job, not because the framework was written in, or because it’s new and shiny, or because other developers use it, select a tool because it is the best fit for the given requirements.


So if you ask me if I use Typescript or ES2015, my first question will be, what is the scenario or use case, then I can answer based on the above criteria.

Hope this helps someone and have a great day.

Just a grain of sand on the worlds beaches.


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