Stevenmasley/wasm

.gitignore

@@ -1 +1,4 @@
-.idea
+.idea
+
+# build artifacts
+build/

Makefile

@@ -1,8 +1,17 @@
+GO_SRC_FILES := $(shell find . $(FIND_EXCLUSIONS) -type f -name '*.go' -not -name '*_test.go')
+
 .PHONY: gen
 gen:
 	@echo "Generating code..."
 	go generate ./...
 
 .PHONY: clean-testdata
 clean-testdata:
-	git clean -xfd testdata
+	git clean -xfd testdata
+
+.PHONY: build-wasm
+build-wasm: site/public/build/preview.wasm
+	mkdir -p ./build
+
+site/public/build/preview.wasm: $(GO_SRC_FILES)
+	GOOS=js GOARCH=wasm go build -o ./build/preview.wasm ./cmd/wasm

cmd/wasm/main.go

@@ -0,0 +1,87 @@
+//go:build js && wasm
+
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io/fs"
+	"path/filepath"
+	"syscall/js"
+
+	"github.com/spf13/afero"
+
+	"github.com/coder/preview"
+	"github.com/coder/preview/types"
+)
+
+func main() {
+	// Create a channel to keep the Go program alive
+	done := make(chan struct{})
+
+	// Expose the Go function `fibonacciSum` to JavaScript
+	js.Global().Set("go_preview", js.FuncOf(tfpreview))
+	js.Global()
+
+	// Block the program from exiting
+	<-done
+}
+
+func tfpreview(this js.Value, p []js.Value) any {
+	tf, err := fileTreeFS(p[0])
+	if err != nil {
+		return err
+	}
+
+	output, diags := preview.Preview(context.Background(), preview.Input{
+		PlanJSONPath:    "",
+		PlanJSON:        nil,
+		ParameterValues: nil,
+		Owner:           types.WorkspaceOwner{},
+	}, tf)
+
+	data, _ := json.Marshal(map[string]any{
+		"output": output,
+		"diags":  diags,
+	})
+	return js.ValueOf(string(data))
+}
+
+func fileTreeFS(value js.Value) (fs.FS, error) {
+	data := js.Global().Get("JSON").Call("stringify", value).String()
+	var filetree map[string]any
+	if err := json.Unmarshal([]byte(data), &filetree); err != nil {
+		return nil, err
+	}
+
+	mem := afero.NewMemMapFs()
+	loadTree(mem, filetree)
+
+	return afero.NewIOFS(mem), nil
+}
+
+func loadTree(mem afero.Fs, fileTree map[string]any, path ...string) {
+	dir := filepath.Join(path...)
+	err := mem.MkdirAll(dir, 0755)
+	if err != nil {
+		fmt.Printf("error creating directory %q: %v\n", dir, err)
+	}
+	for k, v := range fileTree {
+		switch vv := v.(type) {
+		case string:
+			fn := filepath.Join(dir, k)
+			f, err := mem.Create(fn)
+			if err != nil {
+				fmt.Printf("error creating file %q: %v\n", fn, err)
+				continue
+			}
+			_, _ = f.WriteString(vv)
+			f.Close()
+		case map[string]any:
+			loadTree(mem, vv, append(path, k)...)
+		default:
+			fmt.Printf("unknown type %T for %q\n", v, k)
+		}
+	}
+}

go.mod

@@ -19,6 +19,7 @@ require (
 	github.com/hashicorp/terraform-plugin-sdk/v2 v2.36.1
 	github.com/jedib0t/go-pretty/v6 v6.6.7
 	github.com/quasilyte/go-ruleguard/dsl v0.3.22
+	github.com/spf13/afero v1.12.0
 	github.com/stretchr/testify v1.10.0
 	github.com/zclconf/go-cty v1.16.3
 	golang.org/x/xerrors v0.0.0-20240903120638-7835f813f4da

go.sum

@@ -1160,6 +1160,8 @@ github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72/go.mod h1:JwIasO
 github.com/spf13/afero v1.3.3/go.mod h1:5KUK8ByomD5Ti5Artl0RtHeI5pTF7MIDuXL3yY520V4=
 github.com/spf13/afero v1.6.0/go.mod h1:Ai8FlHk4v/PARR026UzYexafAt9roJ7LcLMAmO6Z93I=
 github.com/spf13/afero v1.9.2/go.mod h1:iUV7ddyEEZPO5gA3zD4fJt6iStLlL+Lg4m2cihcDf8Y=
+github.com/spf13/afero v1.12.0 h1:UcOPyRBYczmFn6yvphxkn9ZEOY65cpwGKb5mL36mrqs=
+github.com/spf13/afero v1.12.0/go.mod h1:ZTlWwG4/ahT8W7T0WQ5uYmjI9duaLQGy3Q2OAl4sk/4=
 github.com/spf13/pflag v1.0.6 h1:jFzHGLGAlb3ruxLB8MhbI6A8+AQX/2eW4qeyNZXNp2o=
 github.com/spf13/pflag v1.0.6/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
 github.com/spiffe/go-spiffe/v2 v2.5.0 h1:N2I01KCUkv1FAjZXJMwh95KK1ZIQLYbPfhaxw8WS0hE=