diff --git a/cmd/gogio/jsbuild.go b/cmd/gogio/jsbuild.go
index 63bf07b3..72b4fb60 100644
--- a/cmd/gogio/jsbuild.go
+++ b/cmd/gogio/jsbuild.go
@@ -4,10 +4,13 @@ package main
import (
"fmt"
+ "golang.org/x/tools/go/packages"
+ "io"
"io/ioutil"
"os"
"os/exec"
"path/filepath"
+ "strings"
)
func buildJS(bi *buildInfo) error {
@@ -35,34 +38,93 @@ func buildJS(bi *buildInfo) error {
if err != nil {
return err
}
- const indexhtml = `
+ if err := ioutil.WriteFile(filepath.Join(out, "index.html"), []byte(jsIndex), 0600); err != nil {
+ return err
+ }
+ goroot, err := runCmd(exec.Command("go", "env", "GOROOT"))
+ if err != nil {
+ return err
+ }
+ wasmJS := filepath.Join(goroot, "misc", "wasm", "wasm_exec.js")
+ if _, err := os.Stat(wasmJS); err != nil {
+ return fmt.Errorf("failed to find $GOROOT/misc/wasm/wasm_exec.js driver: %v", err)
+ }
+ pkgs, err := packages.Load(&packages.Config{
+ Mode: packages.NeedName | packages.NeedFiles | packages.NeedImports | packages.NeedDeps,
+ Env: append(os.Environ(), "GOOS=js", "GOARCH=wasm"),
+ }, bi.pkgPath)
+ if err != nil {
+ return err
+ }
+ extraJS, err := findPackagesJS(pkgs[0], make(map[string]bool))
+ if err != nil {
+ return err
+ }
+
+ return mergeJSFiles(filepath.Join(out, "wasm.js"), append([]string{wasmJS}, extraJS...)...)
+}
+
+func findPackagesJS(p *packages.Package, visited map[string]bool) (extraJS []string, err error) {
+ if len(p.GoFiles) == 0 {
+ return nil, nil
+ }
+ js, err := filepath.Glob(filepath.Join(filepath.Dir(p.GoFiles[0]), "*_js.js"))
+ if err != nil {
+ return nil, err
+ }
+ extraJS = append(extraJS, js...)
+ for _, imp := range p.Imports {
+ if !visited[imp.ID] {
+ extra, err := findPackagesJS(imp, visited)
+ if err != nil {
+ return nil, err
+ }
+ extraJS = append(extraJS, extra...)
+ visited[imp.ID] = true
+ }
+ }
+ return extraJS, nil
+}
+
+// mergeJSFiles will merge all files into a single `wasm.js`. It will prepend the jsSetGo
+// and append the jsStartGo.
+func mergeJSFiles(dst string, files ...string) (err error) {
+ w, err := os.Create(dst)
+ if err != nil {
+ return err
+ }
+ defer func() {
+ if cerr := w.Close(); err != nil {
+ err = cerr
+ }
+ }()
+ _, err = io.Copy(w, strings.NewReader(jsSetGo))
+ if err != nil {
+ return err
+ }
+ for i := range files {
+ r, err := os.Open(files[i])
+ if err != nil {
+ return err
+ }
+ _, err = io.Copy(w, r)
+ r.Close()
+ if err != nil {
+ return err
+ }
+ }
+ _, err = io.Copy(w, strings.NewReader(jsStartGo))
+ return err
+}
+
+const (
+ jsIndex = `
-
-
+
@@ -70,16 +132,31 @@ func buildJS(bi *buildInfo) error {
`
- if err := ioutil.WriteFile(filepath.Join(out, "index.html"), []byte(indexhtml), 0600); err != nil {
- return err
+ // jsSetGo sets the `window.go` variable.
+ jsSetGo = `(() => {
+ window.go = {argv: [], env: {}, importObject: {go: {}}};
+ window.go["argv"] = (new URLSearchParams(location.search).get("argv") ?? "").split(" ");
+})();`
+ // jsStartGo initializes the main.wasm.
+ jsStartGo = `(() => {
+ defaultGo = new Go();
+ Object.assign(defaultGo["argv"], go["argv"]);
+ Object.assign(defaultGo["env"], go["env"]);
+ for (let key in go["importObject"]) {
+ if (typeof defaultGo["importObject"][key] === "undefined") {
+ defaultGo["importObject"][key] = {};
+ }
+ Object.assign(defaultGo["importObject"][key], go["importObject"][key]);
}
- goroot, err := runCmd(exec.Command("go", "env", "GOROOT"))
- if err != nil {
- return err
- }
- wasmjs := filepath.Join(goroot, "misc", "wasm", "wasm_exec.js")
- if _, err := os.Stat(wasmjs); err != nil {
- return fmt.Errorf("failed to find $GOROOT/misc/wasm/wasm_exec.js driver: %v", err)
- }
- return copyFile(filepath.Join(out, "wasm_exec.js"), wasmjs)
-}
+ window.go = defaultGo;
+ if (!WebAssembly.instantiateStreaming) { // polyfill
+ WebAssembly.instantiateStreaming = async (resp, importObject) => {
+ const source = await (await resp).arrayBuffer();
+ return await WebAssembly.instantiate(source, importObject);
+ };
+ }
+ WebAssembly.instantiateStreaming(fetch("main.wasm"), go.importObject).then((result) => {
+ go.run(result.instance);
+ });
+})();`
+)