For the selection of new projects, should koa1 plus nodejs6.5, koa2 plus babel, or typescript be used?

  node.js, question

For the selection of new projects, should koa1 plus nodejs6.5, koa2 plus babel, or typescript be used?

The current requirements of the project can be predicted to have about 40,000 lines of code (js native), but I don’t know how I should choose the technology based on the current situation. nodejs can choose to use stable version or the latest release.
The project is not particularly critical (I mean, it doesn’t matter if it lasts for 10 minutes).

My idea is:

  1. One step as far as possible means adopting more radical grammar and features instead of KOA1/Generator/Yield; However, this is also a very safe solution, with abundant module and middleware, which can be found everywhere.

  2. Koa2 plus babel or tsc looks like modern, and in ES7 or later versions, after await/async is included in the standard, it should be the final plan to reject callback hell.

ps:
Team inside’s people have written express, koa1, java, c# and are already online.

I’m playing koa2 and TypeScript, and it’s very cool to write it after the pit is removed. For example, code like this:

@router('post', '/user/logout')
 async logout(ctx, next) {
 ctx.body = 'logout!'  ;
 await next();
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