Added JavaScript/wasm target via emscripten

[RicBent]

This pull requests adds a build target for a JavaScript library, usable in any modern Browser.
For this the emscripten toolchain is utilized.

Solves #169

You can check out a running demo here: https://ricbent.github.io/Kiwi/demo/

Things that can be improved:

• More of the base API functionality (multiple results, custom builder arguments, etc)
• Implementation of wasm 128-bit SIMD functions (supported in all current browsers: https://caniuse.com/wasm-simd)
• Addition of GitHub actions to build this new target
• Creating a proper npm package (package.json, helpers like the WebWorker wrapper from the demo, TypeScript types, etc), deployed via GitHub actions
• Usage of wizer to pre-initialize the wasm module with a dictionary. This would entirely bypass the slow Kiwi initialization times.
• Multi-thread support via WebWorkers
• Add Documentation

Because I haven't set up GitHub actions for this target yet, you need to manually build. This requires the emscripten toolchain to be installed:

mkdir build
cd build
emcmake cmake -DCMAKE_BUILD_TYPE=Release -DKIWI_USE_CPUINFO=OFF -DKIWI_BUILD_TEST=OFF -DKIWI_USE_MIMALLOC=OFF -DKIWI_BUILD_CLI=OFF -DKIWI_BUILD_EVALUATOR=OFF -DKIWI_BUILD_MODEL_BUILDER=OFF ../
make

This will generate kiwi-wasm.js and kiwi-wasm.wasm. The former can be directly used in any modern browser.

Sorry if I didn't follow some contribution guidelines correctly as I don't speak much Korean (yet).

---

Things changed since the creation of the PR:

• Bindings implement the same functionality as the Java bindings, instead of just the tokenize/build functions
• Typing for all api via TypeScript
• Inline code documentation, HTML docs can be generated, just like the C++/C/Python bindings
• npm package should be publishable by release workflow
• demo project that uses the npm package is provided, replicating the linked demo, now with proper typing

[RicBent]

Is this change correct? RicBent@3f0eb0c

Passing 0 for numThreads to prevent the ThreadPool creation in KiwiBuilder did not work as that triggered some assertion.

[RicBent]

Attempted to implement the release workflow. Not sure how to test it properly without triggering a release.

I guess a workflow that triggers on new pull requests still needs to be added.

[bab2min]

@RicBent
Wow, it's amazing! Thank you for your contribution! The demo seems to work very well.
I'll review it as soon as possible.

[RicBent]

Great!

The latest commit adds a wrapper package that could be directly imported in any npm project. Along with proper types for the entirety of the so far exposed API (https://github.com/bab2min/Kiwi/blob/2161cf137b996471383e7c7b65370e9f28981f14/bindings/wasm/package/src/kiwi.ts).

I'd be happy to implement the remaining API functionality to bring it to the same level as the Python library once you had a look at the PR.

[bab2min]

@RicBent
Oh, it looks good to me. 👍
I would really appreciate it if the rest of the functionality was completed as well.
If it is difficult for you to implement all the functionality, I think it is okay to implement only the core, merge and release them first, and then supplement the rest later.

[RicBent]

I had a look at the Java bindings and it seems like the only missing API is the following:

KiwiBuilder:

• Init with TypoTransformer
• Add word
• Add pre-analyzed word
• Load additional dictionaries

Kiwi:

• Analyze/tokenize with blocklist
• Analyze/tokenize with pre-tokenized spans

I would also like to add documentation to the bindings. However I am not able to make them in Korean, only in English. Is that a problem @bab2min ?

Oh and we would also need an npm package name as 'kiwi' is already taken. I chose 'kiwi-nlp' for now, but I can change it if you have a better suggestion.

[bab2min]

@RicBent
It's okay to write the documentation in English. If you write the documentation in English, I can translate it for Korean documentation.
I think kiwi-nlp is a good name for the package, showing that it is a NLP library.
Thank you for your contribution!

[RicBent]

Alright, I am almost there then. I already wrote pretty much all the required documentation and just the 4 points from KiwiBuilder are missing to match the Java API functionality.

I also amended the release workflow to automatically build and publish the resulting package to npm:

Kiwi/.github/workflows/release.yml

Lines 330 to 346 in c77e15f

	build-emscripten:
	name: Emscripten
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2
	with:
	submodules: true
	lfs: true
	- uses: mymindstorm/setup-emsdk@v14
	- name: Build
	run: |
	cd bindings/wasm
	./build.sh
	- uses: JS-DevTools/npm-publish@v3
	with:
	token: ${{ secrets.NPM_TOKEN }}
	package: bindings/wasm/package

The workflow requires NPM_TOKEN to be added to the repo's secrets on your end when this gets merged.

To generate an npm token you need to do the following:

1. Register an account on npm if you didn't already
2. Follow this to create a token (the token will need write access to the kiwi-nlp package)

To add it to the repo's secrets you can follow this:
https://docs.github.com/en/actions/security-guides/using-secrets-in-github-actions

[RicBent]

@bab2min everything on my end should be done now:

• The TypeScript bindings implement the same functionality as the Java bindings
• Inline code documentation is done, HTML docs can be generated, just like the Python bindings
• npm package should be publishable by release workflow (needs token as described)
• demo project that uses the npm package is provided, replicating this: https://ricbent.github.io/Kiwi/demo/

Let me know if anything needs to be improved/changed!

[bab2min]

@RicBent
Great!!! Thank you for your contribution.
I'll add documentations for Korean and tokens for release workflow.