Convert src/ to TypeScript

[tetsuharuohzeki]

Abstract

• Breaking Change (possible)
• From some conversation with @azu on Twitter, I tried to convert codes to TypeScript.
• This changeset includes some changes for build system.
• This change only does rewrite codes with TypeScript. To publish d.ts in npm, we need push more patch onto this.

Motivation

• Increase interoperabitily with static typing world like TypeScript or Flowtype.
• Erase some inconsistency of API system of this library by static checking types of them.

Detailed Design

Change build system

This introduces 2-phase build system.

1. At 1st phase, Try type checking under src/ with tsc and emit a plain JS code into /__obj/ temp dir.
   In this phase, this also try to copy all javascript file into /__obj/ to keep the content of /src/.
2. At 2nd phase, Do down-level transform by babel and emit the transformed one into /lib/.

By this change, we can achive to convert our source code to TypeScript incrementally without at giant single patch file.

Unit tese imports from /lib/

By the above change, we need to load the code to test unit tests for incremental converting without changeing
unit tests.

Convert TypeScript

Convert *.js to *.ts simply.

This change escapes from the problem which is that some dependency does not have any d.ts by dirty hacking.

Add *.d.ts and *.js with same name. TypeScript compiler uses *.d.ts to resolve type checking.
But we use *.js file to load a file actually on the runtime. This dirty hack resolves the problem.

Drawback

• Drop JSDoc.
  • By this change, user who uses Closure Compiler advanced optimization might face to some troubles.
• Increase Complexity of build system.

Alternative Approach

• Using Flowtype instead. This is also possible solution.
  But this tries to use TypeScript by conversations with @azu.

Unresolved Items

• Clean up the build system: feat(typescript): add d.ts to pacakge.json #78.
• Fix some inconsistency of APIs: TypeScript: StoreGroup#getState interface #71
• No emit *.d.ts files into /lib/: feat(typescript): add d.ts to pacakge.json #78.
• Disable power-assert temporary: Re-enable power-assert #83
• Remove jsdoc-to-assert properly: TypeScript-Babel: jsdoc-to-assert is not working #82
• No work documentation build by JSDoc:
• No any linting:
• Reduce any type from public APIs:
• Mark Abstract Class/Property as abstract correctly.
• Relax complex dependency.
  • Some types depends with each other complexly.

[tetsuharuohzeki]

r? @azu

[azu]

Thanks.
I'll look it in this weekend.

[azu]

📝 I have no idea about this.
Can we remove this casting by some changes?

[tetsuharuohzeki]

I thought to introduce some new interfaces which is implemented by StoreGroup or Store to fix it.
Perhaps is it not a right way?

[azu]

Ok, This fix should be later.

[azu]

Store is not abstruct in some test case.

almin/test/Store-test.js

Line 12 in e2daa2f

const store = new Store();

Is it valid in TypeScript?

Of course, Store is just abstract in most case without testing, I think.
Should we will modify test code?

[tetsuharuohzeki]

Is it valid in TypeScript?

"At this time", it's valid in TypeScript because we keep all unit test cases as plain js.
However, of course, we need to add class TestStore extends Store to them if we convert test cases to TypeScript.

[azu]

Ok. I've checked this PR.

The first overview is looks good to me.
Thanks for nice work.

[azu]

Maybe, displayName is optional.

[azu]

ditto.
displayName is optional

[azu]

I've merged this.
Thanks to @saneyuki 👍

Next Steps

We will continue to investigate following TODO issues.

• TypeScript: Add d.ts in npm · Issue #70 · almin/almin
• TypeScript: introduce Type Guards · Issue #72 · almin/almin
• TypeScript: StoreGroup#getState interface · Issue #71 · almin/almin