interface Go {
argv: string[]
importObject: WebAssembly.Imports
run(instance: WebAssembly.Instance): void
}
declare const ESBUILD_VERSION: string
declare function postMessage(message: any): void
onmessage = ({ data: wasm }: { data: WebAssembly.Module | string }) => {
let decoder = new TextDecoder()
let fs = (globalThis as any).fs
let stderr = ''
fs.writeSync = (fd: number, buffer: Uint8Array) => {
if (fd === 1) {
postMessage(buffer)
} else if (fd === 2) {
stderr += decoder.decode(buffer)
let parts = stderr.split('\n')
if (parts.length > 1) console.log(parts.slice(0, -1).join('\n'))
stderr = parts[parts.length - 1]
} else {
throw new Error('Bad write')
}
return buffer.length
}
let stdin: Uint8Array[] = []
let resumeStdin: () => void
let stdinPos = 0
onmessage = ({ data }) => {
if (data.length > 0) {
stdin.push(data)
if (resumeStdin) resumeStdin()
}
}
fs.read = (
fd: number, buffer: Uint8Array, offset: number, length: number,
position: null, callback: (err: Error | null, count?: number) => void,
) => {
if (fd !== 0 || offset !== 0 || length !== buffer.length || position !== null) {
throw new Error('Bad read')
}
if (stdin.length === 0) {
resumeStdin = () => fs.read(fd, buffer, offset, length, position, callback)
return
}
let first = stdin[0]
let count = Math.max(0, Math.min(length, first.length - stdinPos))
buffer.set(first.subarray(stdinPos, stdinPos + count), offset)
stdinPos += count
if (stdinPos === first.length) {
stdin.shift()
stdinPos = 0
}
callback(null, count)
}
let go: Go = new (globalThis as any).Go()
go.argv = ['', `--service=${ESBUILD_VERSION}`]
tryToInstantiateModule(wasm, go).then(
instance => {
postMessage(null)
go.run(instance)
},
error => {
postMessage(error)
},
)
}
async function tryToInstantiateModule(wasm: WebAssembly.Module | string, go: Go): Promise<WebAssembly.Instance> {
if (wasm instanceof WebAssembly.Module) {
return WebAssembly.instantiate(wasm, go.importObject)
}
const res = await fetch(wasm)
if (!res.ok) throw new Error(`Failed to download ${JSON.stringify(wasm)}`)
if ('instantiateStreaming' in WebAssembly && /^application\/wasm($|;)/i.test(res.headers.get('Content-Type') || '')) {
const result = await WebAssembly.instantiateStreaming(res, go.importObject)
return result.instance
}
const bytes = await res.arrayBuffer()
const result = await WebAssembly.instantiate(bytes, go.importObject)
return result.instance
}