# PicoRuby.wasm
PicoRuby.wasm is a PicoRuby port to WebAssembly.
## Usage
```html
DOM manipulation
```
You can also read Ruby scripts from a file:
```html
```
### Fetching
```ruby
require 'js'
logo = JS.document.getElementById('logo')
JS.global.fetch('some.svg') do |response|
if response.status.to_poro == 200
logo.innerHTML = response.to_binary # to_binary blocks until the Promise is resolved
end
end
```
picoruby.wasm doesn't support async/await so to make the binary small.
As of now, GET method is only supported. We'll wait for your PRs!
### JS::Object#to_poro method
As of now, `JS::Object` class doesn't have methods like `to_i` and `to_s`.
Instead, `to_poro`[^1] method converts a JS object to a Ruby object, fallbacking to a JS::Object when not doable.
[^1]: *poro* stands for *Plain Old Ruby Object*.
Other than `JS::Object#to_poro`, you can use `JS::Object#to_binary` to get a binary data from an arrayBuffer.
### Multi tasks
```html
Multi tasks
Open the console and see the output
```
## Ristriction due to the imlementation
Inside callbacks of `addEventListener`, you can't refer to variables outside the block:
```ruby
require 'js'
button = JS.document.getElementById('button')
button.addEventListener('click') do |event|
event.target.innerText = 'Clicked!'
# OK
button.innerText = 'Clicked!'
# => NameError: undefined local variable or method
end
```
The restriction above is only for the `addEventListener`.
You can refer to variables outside the block in general:
```ruby
lvar = 'Hello, PicoRuby!'
3.times do
puts lvar
end
#=> Hello, PicoRuby! (3 times)
```
## Contributing
Fork [https://github.com/picoruby/picoruby](https://github.com/picoruby/picoruby), patch, and send a pull request.
### Build
```sh
git clone https://github.com/picoruby/picoruby
cd picoruby
MRUBY_CONFIG=wasm rake
```
Then, you can start a local server:
```sh
rake wasm:server
```
### Files that you may want to dig into
- `picoruby/mrbgems/picoruby-wasm/*`
- `picoruby/build_config/wasm.rb`
## License
MIT License
2024 (c) HASUMI Hitoshi a.k.a. [@hasumikin](https://twitter.com/hasumikin)