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Go write webassembly

2022-07-21 16:35:00 【AdleyTales】

Environmental Science

golang
javascript
tinygo

Code up

golang

package main

import (
	"crypto/md5"
	"encoding/hex"
	"fmt"
	"strings"
	"syscall/js"
)

//go:export add
func add(x, y int) int {
    
	return x + y
}

const salt = "[email protected]!"

//  Sign the string 
func sign(this js.Value, args []js.Value) interface{
    } {
    
	fmt.Println("============== begin")
	fmt.Println(args[0].String()) //  Enter the reference 
	b := []byte(args[0].String())
	s := []byte(salt)
	h := md5.New()
	h.Write(s) //  Write the salt value first 
	h.Write(b)
	result := hex.EncodeToString(h.Sum(nil))
	fmt.Println(result)
	fmt.Println("============== end")
	return result
}

func main() {
    
	fmt.Println("hello wasm ...")
	
	//  Register to global 
	js.Global().Set("sign", js.FuncOf(sign))

	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)
}

compile go Code ->wasm

tinygo build -o main-tiny.wasm

copy to wasm Bridge to current directory

cp "$(tinygo env TINYGOROOT)/targets/wasm_exec.js" ./wasm_exec_tiny.js

html

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Wasm Demo</title>
  <script src="./wasm_exec_tiny.js"></script>
</head>

<body>

  <script> // polyfill if (!WebAssembly.instantiateStreaming) {
       WebAssembly.instantiateStreaming = async (resp, importObject) => {
       const source = await (await resp).arrayBuffer() return await WebAssembly.instantiate(source, importObject) } } function loadWasm (path) {
       const go = new Go() //  Solve the browser console error  go.importObject.env["syscall/js.finalizeRef"] = () => {
       } return new Promise((resolve, reject) => {
       WebAssembly.instantiateStreaming(fetch(path), go.importObject) .then(result => {
       go.run(result.instance) resolve(result.instance) }) .catch(error => {
       reject(error) }) }) } loadWasm("main-tiny.wasm").then(wasm => {
       const o = {
       name: 'adley', age: 18, data: [12, 32, 'dasd'] } console.log(sign(JSON.stringify(o))) }).catch(error => {
       console.log("ouch", error) }) </script>
</body>

</html>