feat(js): error when GOROOT not found, add dev server to example

.gitignore

@@ -1,3 +1,4 @@
 node_modules
 example/node_modules
 .gocache
+wasm_exec.js

.npmignore

@@ -0,0 +1,3 @@
+example
+wasm
+.gocache

example/.gitignore

@@ -0,0 +1,4 @@
+dist/main.wasm
+dist/main.js
+node_modules
+src/api/main.wasm

example/go.sum

@@ -1,6 +1,2 @@
-gitea.teamortix.com/Team-Ortix/go-mod-wasm/wasm v0.0.0-20210320160445-87f4b612f08a h1:yP+ZWeFYr26sQbkjOZKlJvDdPNzxsdK3T9WeDDpRZ3Y=
-gitea.teamortix.com/Team-Ortix/go-mod-wasm/wasm v0.0.0-20210320160445-87f4b612f08a/go.mod h1:aXGSS5eQ84RFpINcZVu4y/MeaguTCZM9RvZct1OtsE0=
-gitea.teamortix.com/Team-Ortix/go-mod-wasm/wasm v0.0.0-20210320171600-df451aa899a5 h1:1obgUBM+Sx9Hi+2nv05MvPBR8qu/0ZDCRs8JIky8U2o=
-gitea.teamortix.com/Team-Ortix/go-mod-wasm/wasm v0.0.0-20210320171600-df451aa899a5/go.mod h1:aXGSS5eQ84RFpINcZVu4y/MeaguTCZM9RvZct1OtsE0=
 gitea.teamortix.com/Team-Ortix/go-mod-wasm/wasm v0.0.0-20210320172655-205806929b8f h1:A1ImTmMMUKGRvxCXO+hQh92DAsRz37ioQGlg8dpxFjc=
 gitea.teamortix.com/Team-Ortix/go-mod-wasm/wasm v0.0.0-20210320172655-205806929b8f/go.mod h1:aXGSS5eQ84RFpINcZVu4y/MeaguTCZM9RvZct1OtsE0=

example/package.json

@@ -5,16 +5,16 @@
   "private": true,
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1",
-    "start": "GOROOT=`go env GOROOT` webpack"
+    "start": "GOROOT=`go env GOROOT` webpack serve"
   },
   "author": "",
   "license": "ISC",
   "devDependencies": {
     "webpack": "^5.27.0",
-    "webpack-cli": "^4.5.0"
+    "webpack-cli": "^4.5.0",
+    "webpack-dev-server": "^3.11.2"
   },
   "dependencies": {
-    "crypto-browserify": "^3.12.0",
-    "loader-utils": "^2.0.0"
+    "crypto-browserify": "^3.12.0"
   }
 }

example/src/api/main.go

@@ -8,7 +8,9 @@ import (
 
 func main() {
 	c := make(chan bool, 0)
-	fmt.Println("Hello Go!")
+
+	fmt.Println("Hello from go-mod-wasm!")
+
 	wasm.Ready()
 	<-c
 }

example/src/index.js

@@ -1,6 +1,5 @@
-import wasm from './main.go';
+import wasm from './api/main.go';
 
 (async () => {
-    console.log(wasm)
-    console.log(await wasm.test(), "..")
+
 })()

example/webpack.config.js

@@ -2,6 +2,11 @@ const path = require('path');
 
 module.exports = {
     entry: './src/index.js',
+    devServer: {
+        contentBase: path.resolve(__dirname, 'dist'),
+        compress: true,
+        port: 3000,
+    },
     mode: "production",
     output: {
         filename: 'main.js',
@@ -36,4 +41,14 @@ module.exports = {
             }
         ]
     },
+    performance: {
+        assetFilter: (file) => {
+            return !/\.wasm/.test(file)
+        }
+    },
+    ignoreWarnings: [
+        {
+            module: /wasm_exec.js$/
+        }
+    ]
 };

index.js

@@ -1,8 +1,7 @@
 const fs = require("fs")
-const { execSync, execFileSync } = require("child_process")
+const { execFileSync } = require("child_process")
 const path = require("path")
 const { lookpath } = require("lookpath")
-const { executionAsyncResource } = require("async_hooks")
 
 const exists = async (dir, file) => {
     return new Promise((res, rej) => {
@@ -23,6 +22,11 @@ module.exports = function (source) {
         return cb(new Error("go bin not found in path."));
     }
 
+    if (!process.env.GOROOT) {
+        return cb(new Error("Could not find GOROOT in environment.\n" +
+            "Please try adding this to your script:\nGOROOT=`go env GOROOT` npm run ..."))
+    }
+
     const parent = path.dirname(this.resourcePath)
     const outFile = this.resourcePath.slice(0, -2) + "wasm"
     let modDir = parent
@@ -59,7 +63,11 @@ module.exports = function (source) {
             return cb(e)
         }
 
-        const wasmPath = path.join(process.env.GOROOT, "misc", "wasm", "wasm_exec.js")
+        const wasmOrigPath = path.join(process.env.GOROOT, "misc", "wasm", "wasm_exec.js")
+        const wasmEmitPath = path.join(__dirname, 'wasm_exec.js')
+        if (!(await exists(__dirname, 'wasm_exec.js'))) {
+            fs.copyFileSync(wasmOrigPath, wasmEmitPath)
+        }
 
         let contents = fs.readFileSync(outFile)
         fs.unlinkSync(outFile)
@@ -69,7 +77,7 @@ module.exports = function (source) {
         this.addContextDependency(modDir)
 
         cb(null,
-            `require('!${wasmPath}')
+            `require('!${wasmEmitPath}')
 import goWasm from '${path.join(__dirname, 'bridge.js')}';
 
 const wasm = fetch('${emitPath}').then(response => response.arrayBuffer())

package.json

@@ -1,11 +1,8 @@
 {
   "name": "go-mod-wasm",
-  "version": "0.0.1",
-  "description": "whatever",
+  "version": "0.1.2",
+  "description": "A webpack-based configuration to work with wasm using Go.",
   "main": "index.js",
-  "scripts": {
-    "test": "echo \"Error: no test specified\" && exit 1"
-  },
   "repository": {
     "type": "git",
     "url": "https://gitea.teamortix.com/Team-Ortix/go-mod-wasm"