go语言打包的网页wasm示例详解

基本环境

有时需要做一些前端的数据处理，但是又不想把数据出来的方式就这么简单的暴露在js里，然后就用了wasm来包装这个处理函数，当然，这样也能提高性能。

新建文件 index.js

const fastify = require('fastify')({ logger: true })
const path = require('path')
// Serve the static assets
fastify.register(require('fastify-static'), {
   root: path.join(__dirname, ''),
   prefix: '/'
})
const start = async () => {
   try {
       await fastify.listen(8080, "0.0.0.0")
       fastify.log.info(`server listening on ${fastify.server.address().port}`)
   } catch (error) {
       fastify.log.error(error)
   }
}
start()

package.json

{
  "scripts": {
    "dev": "node index.js"
  },
  "dependencies": {
    "fastify": "^3.6.0",
    "fastify-static": "^3.2.1"
  }
}

index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>hello</title>
</head>
<body>
hello
</body>
</html>

运行 npm run dev 打开http://127.0.0.1:8080

wasm部分

新建 go.mod

module hello-world
go 1.18

main.go

package main
import (
	"syscall/js"
)
func main() {
	message := "👋 Hello World 🌍"
	document := js.Global().Get("document")
	h2 := document.Call("createElement", "h2")
	h2.Set("innerHTML", message)
	document.Get("body").Call("appendChild", h2)
	<-make(chan bool)
}

go env

GOOS=windows
GOARCH=amd64

set GOOS=jsset GOARCH=wasm

cp "$(go env GOROOT)/misc/wasm/wasm_exec.js" .wasm_exec.js

go build -o main.wasmmain.wasm

index.html

<html>
<head>
    <meta charset="utf-8"/>
    <script src="wasm_exec.js"></script>
</head>
<body>
<h1>WASM</h1>
<script>
	// 判断是否支持instantiateStreaming加载
    if (!WebAssembly.instantiateStreaming) {
        WebAssembly.instantiateStreaming = async (resp, importObject) => {
            const source = await (await resp).arrayBuffer()
            return await WebAssembly.instantiate(source, importObject)
        }
    }
    // 异步加载wasm文件
    function loadWasm(path) {
        const go = new Go()
        return new Promise((resolve, reject) => {
            WebAssembly.instantiateStreaming(fetch(path), go.importObject)
                .then(result => {
                    go.run(result.instance)
                    resolve(result.instance)
                })
                .catch(error => {
                    reject(error)
                })
        })
    }
    //加载wasm文件
    loadWasm("main.wasm").then(wasm => {
        console.log("wasm已加载 👋")
    }).catch(error => {
        console.log("加载出错了", error)
    })
</script>
</body>
</html>

然后刷新浏览器就能看到这么一个界面

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go语言打包的网页wasm示例详解

目录

基本环境

wasm部分