Move codebase to ES6

[jankapunkt]

This would be a big task but I think there will be lots of benefits in terms of code-readability (especially with template-literals) and a few performance improvements either.

This could be also distributed to PR-per-package:

• blaze
• blaze-tools
• caching-html-compiler (PR: Move package caching-html-compiler to ES6 #390)
• html-tools (PR: Refactored html-tools and htmljs to move ES6 version #385)
• htmljs (PR: Refactored html-tools and htmljs to move ES6 version #385)
• observe-sequence
• spacebars
• spacebars-compiler
• spacebars-tests
• templating-compiler (PR: Move package templating compiler es6 #389)
• templating-runtime
• templating-tools
• ui (PR: Deprecate UI package #391)

In an optimum there would be no changes to the functionality at all.

• PR for adding a linter: Add linter #382

[StorytellerCZ]

We could also go one step further and move to TypeScript. 😄

[jankapunkt]

We could but I have no TS experience at all so to me it would take much more time to get into the ts thinking

[StorytellerCZ]

Alright let's take it step by step.

[jankapunkt]

I think a good starting point for moving towards TS would be to add type definitions at least, so intellisense can pick it up better.

[rashmod]

I'm willing to do this.
I'm new to open source and this seems like a good issue to resolve. Is there anything that I must know about this project or anything else?

[jankapunkt]

Great @rashmod !!!

Please do one PR per package (Thie repo contains multiple packages). Since you are new it may be a good start by using a smaller package.

Another thing that's still not discussed is which linter we use cc @StorytellerCZ @denihs

[rashmod]

Okay, then I'll start with the smaller packages. But when you say convert to es6 are you just talking about changing the var to let const or anything more. I want to be more explicit about the scope of this thing before starting.

[jankapunkt]

I woul say use const and let and all newer Methods from Object / Array and String that became available since ES6 (where applicable).

Also favour destructuring and named parameters incl. parameter defaults where applicable.

Note: arrow functions should be used with care since there are many binding going in Blaze with functions using this a lot.

Don't worry, just start and we will review anyway. If there are things left to be improved etc. we will let you know and you will have enough support to get this done right 👍

[rashmod]

I will start working on this now. But @jankapunkt you were talking about the linter to use.....?

[jankapunkt]

I just checked and the main Meteor project uses the @quave/quave config (see their package.json) which is maintained by @filipenevola so I think we should also adapt to use it.

What do you think @StorytellerCZ @denihs

[denihs]

No objection from me