Module: Dommy::Js::Wasmtime

Defined in:
lib/dommy/js/wasmtime.rb,
lib/dommy/js/wasmtime/vm.rb,
lib/dommy/js/wasmtime/version.rb,
lib/dommy/js/wasmtime/engines/quickjs.rb

Overview

A wasmtime-rb host for mruby-wasm-js builds, bridged to a Dommy DOM. The wasmtime sibling of dommy-js-quickjs: it runs mruby (inside wasm on wasmtime) and serves its ‘js.*` interop from a real JS world — a QuickJS VM bound to Dommy (dommy-js-quickjs) — so `JS.global` is real globalThis, promises/await/fetch work, and the same DOM the wasm mutates is inspectable from Ruby. Any mruby-wasm-js build works; the Lilac component runtime is the primary example.

require "dommy"
require "dommy/js/wasmtime"

vm = Dommy::Js::Wasmtime.boot(
  wasm: "build/app.wasm",
  html: File.read("index.html"),
  sources: %w[lib/foo.rb lib/bar.rb …],       # mruby source files
  entrypoint: "Lilac.start",                  # app boot call (or nil)
) do |engine|
  engine.eval(<<~JS)                          # seed the JS world
    globalThis.fetch = async (u) => new Response(DATA_JSON, {…});
  JS
end
vm.document.query_selector(".app")            # driven by the mruby app

Defined Under Namespace

Modules: Engines Classes: Error, RubyError, VM

Constant Summary collapse

VERSION = 
"0.1.0"

Class Method Summary collapse

Class Method Details

.boot(wasm:, html: nil, window: nil, sources: [], entrypoint: nil) {|engine| ... } ⇒ VM

Build a VM over a Dommy DOM, optionally seed the JS world (fetch stub, globals), load the mruby source files, and run an app boot call — the Ruby equivalent of a browser bootstrap script.

Parameters:

  • wasm (String) —

    path to the mruby-wasm-js .wasm

  • html (String, nil) (defaults to: nil) —

    HTML to parse into the window’s document

  • window (Dommy::Window, nil) (defaults to: nil) —

    explicit window (overrides html)

  • sources (Array<String>) (defaults to: []) —

    mruby source file paths (loaded in order)

  • entrypoint (String, nil) (defaults to: nil) —

    mruby expression to eval after sources load (e.g. “Lilac.start” to mount components); nil to skip

Yields:

  • (engine) —

    optional hook to seed the JS world before sources load

Returns:



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# File 'lib/dommy/js/wasmtime.rb', line 47

def self.boot(wasm:, html: nil, window: nil, sources: [], entrypoint: nil)
  require_relative "wasmtime/engines/quickjs"
  win = window || Dommy.parse(html.to_s)
  vm = nil
  engine = Engines::Quickjs.new(invoke: ->(id, args) { vm.invoke_callback(id, args) }, window: win)
  vm = VM.new(wasm: wasm, engine: engine)
  yield engine if block_given?
  Array(sources).each { |path| vm.eval!(::File.read(path.to_s)) }
  vm.eval!(entrypoint) if entrypoint
  vm
end