Files
kjol/go/cmd/kjol-web/wasm/main.go

54 lines
2.2 KiB
Go

//go:build js && wasm
// Command wasm is the client entry point: it wires client capabilities into the
// (generated) routes, then hydrates the server-rendered DOM or renders fresh.
package main
import (
"kjolweb/app"
"kjol/vdom"
"kjol/wasmruntime"
)
func main() {
// (The client transport for httputil.FetchGob / FetchJSON needs no wiring —
// importing wasmruntime installs it. On the server it stays nil, so those
// fetches no-op during SSR and the page ships its loading state.)
//
// Collect the signals created during setup so their values can be preserved
// across an in-place hot swap. On a normal load RestoreState is nil (fresh
// state); after a dev hot-reload it carries the previous instance's values,
// which NewSignal restores by creation order.
collector := vdom.BeginCollect(wasmruntime.RestoreState())
router := wasmruntime.NewRouter()
deps := app.Deps{Path: router.Path, Navigate: router.Navigate}
routes := app.Routes(deps)
vdom.EndCollect() // signals created later (during renders) aren't preserved
wasmruntime.PreserveState(collector)
render := func() *vdom.VNode { return app.Shell(deps, routes) }
if wasmruntime.HasServerContent() {
wasmruntime.Hydrate(render) // static route: adopt the server-rendered DOM
} else {
wasmruntime.Run(render) // client-rendered route
}
// Adopt the theme AFTER mounting. The class is already on <html> — the document's
// boot script put it there before the first paint — so this is not what makes the
// page dark; it is what makes the SWITCH know which way it is pointing, and what
// keeps the page following the OS if the user never touched the switch.
//
// The server rendered this button not knowing the theme (it cannot: the preference is
// in localStorage), so it drew the wrong icon. Init's signal write re-renders it, and
// the reconciler patches the one button. That mismatch is inherent, not a bug — it is
// the same reason the boot script has to exist at all.
//
// This line used to be unreachable: Hydrate ended in a `select {}` and never returned.
// See wasmruntime.Wait.
app.Theme.Init()
// Last line, always: a Go/wasm main that returns is a dead program, and every event
// handler on the page dies with it.
wasmruntime.Wait()
}