WebAssembly - Working with Go - Adglob Infosystem Pvt Ltd

Working with Go has added support for WebAssembly from version 1.1 onwards. To test it first download, Go.

Go to the golang site, which is available at https://golang.org/dl/ and click on Download Go. As per your operating system download and install Go.

Once done, write a simple program that adds two numbers in go.

testnum.go

package main
import "fmt"
func main() { 
   var a int = 100 
   var b int = 200 
   var ret int 
   ret = sum(a, b) 
   fmt.Printf( "Sum is : %d\n", ret ) 
}
 
/* function returning the max between two numbers */ 
func sum(num1, num2 int) int { 
   return num1+num2 
}

To compile above code to wasm, first set the environment variables in Go.

You will have to run following command −

Set GOOS=js
GOARCH=wasm

Once done, execute the below command −

go build -o testnum.wasm testnum.go

You should get testnum.wasm file once the command is executed.

Let us now test the code in the browser. To do that, we need to get the wasm_exec.js, that is installed with go.

The file wasm_exec.js will be available inside misc/wasm/ folder in go.

Example

Here, is the code for testgo.html that makes use of wasm_exec.js and testnum.wasm.

<html> 
   <head> 
      <meta charset="utf-8"/>
      <script src="wasm_exec.js"></script>
   </head>
   <body>
      <script type="text/javascript"> 
         const importObj = {
            module: {} 
         };
         const go = new Go(); 
         async function fetchAndInstantiate() { 
            const response = await fetch("testnum.wasm"); 
            const buffer = await response.arrayBuffer(); 
            const obj = await WebAssembly.instantiate(buffer, go.importObject); 
            console.log(obj); 
            go.run(obj.instance); 
         } 
         fetchAndInstantiate(); 
      </script>
   </body>
</html>

Output

The output is as follows −

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