WebAssembly can compile other languages such as C/Go/Rust into wasm executable binary files, and then execute wasm through the browser.
This article takes the Go language as an example to introduce the introduction of WebAssembly.
1. Write the main.go file, get the js object in the Go code, and execute the js code.
Introduced syscall/jsto get the js object through js.Global().Get().
js.Global().Get()Both functions and DOM elements can be obtained. The type is js.Value.
Such as: js.Global().Get("alert")
package main
import (
"fmt"
"syscall/js"
)
func main() {
fmt.Println("Hello, Go WebAssembly!")
alert := js.Global().Get("alert")
alert.Invoke("Hello, Go WebAssembly!")
}
2. Build main.go into a wasm binary file
GOOS=js GOARCH=wasm go build -o lib.wasm main.go
3. Copy JavaScript dependencies to the current path
cp "$(go env GOROOT)/misc/wasm/wasm_exec.js" .
4. Create index.html, import wasm_exec.js, and call lib.wasm built in the second step
<html>
<head>
<meta charset="utf-8">
<script src="wasm_exec.js"></script>
<script>
const go = new Go();
WebAssembly.instantiateStreaming(fetch("lib.wasm"), go.importObject).then((result) => {
go.run(result.instance);
});
</script>
</head>
<body>
</body>
</html>
5. Create server.go to listen on port 8080 and serve the current path
package main
import (
"net/http"
"log"
)
func main() {
err := http.ListenAndServe(":8080", http.FileServer(http.Dir(".")))
log.Fatalln(err)
}
6. Start the service
go run server.go
browser access http://localhost:8080.
We can see that the browser console prints fmt.Println("Hello, Go WebAssembly!")output results. And the page pops up a pop-up window for go to call alert.
