fix: show helpful error message when port is occupied (#5146)

* Fix error where incorrect error is raised when the selected port is in use
* Styling fixes, and use string.prototype.startsWith

src/main/index.js

@@ -361,7 +361,9 @@ app.on('ready', async () => {
     });
 
     integrations.on("start-error", err => {
-      err.code = "CUSTOMERROR";
+      if (err.code === undefined) {
+        err.code = "CUSTOMERROR";
+      }
       err.key = "workspace.server.chain";
       err.value = err.message + "\n\n" + err.stack;
       err.tab = "server";

static/node/chain/chain.ethereum.js

@@ -108,9 +108,16 @@ async function startServer(options) {
   try {
     await server.listen(options.port, options.hostname);
   } catch (err) {
+    const { message, stack } = err;
+    let { code } = err;
+    // todo: we may be able to remove this check once https://github.com/trufflesuite/ganache/issues/4020 is resolved
+    if (code === undefined && message && message.startsWith("listen EADDRINUSE")) {
+      code = "EADDRINUSE";
+    }
+
     process.send({
       type: "start-error",
-      data: { code: err.code, stack: err.stack, message: err.message },
+      data: { code, stack, message },
     });
     return;
   }

static/node/chain/chain.ethereum.v2.js

@@ -19,6 +19,7 @@ process.on("unhandledRejection", err => {
 
 process.on("uncaughtException", err => {
   //console.log('uncaught exception:', err.stack || err)
+  // hilariously EADDRINUSE errors will get raised here
   process.send({ type: "error", data: copyErrorFields(err) });
 });
 

static/node/chain/chain.filecoin.js

@@ -48,7 +48,7 @@ async function stopServer() {
 async function startServer(options) {
   await stopServer();
 
-  let sanitizedOptions = Object.assign({}, options);
+  const sanitizedOptions = Object.assign({}, options);
   if (sanitizedOptions.chain && sanitizedOptions.chain.mnemonic) {
     delete sanitizedOptions.chain.mnemonic;
   }
@@ -108,7 +108,16 @@ async function startServer(options) {
   try {
     await server.listen(options.port, options.hostname);
   } catch (err) {
-    process.send({ type: "start-error", data: {code: err.code, stack: err.stack, message: err.message} });
+    const { message, stack } = err;
+    let { code } = err;
+    // todo: we may be able to remove this check once https://github.com/trufflesuite/ganache/issues/4020 is resolved
+    if (code === undefined && message && message.startsWith("listen EADDRINUSE")) {
+      code = "EADDRINUSE";
+    }
+
+    process.send({ type: "start-error", 
+      data: { code, stack, message },
+    });
     return;
   }