slavafomin · June 3, 2025 17:54 · Nov 18, 2021 · Nov 18, 2021 · Oct 9, 2017 · Nov 28, 2016
diff --git a/nodejs-custom-es6-errors.md b/nodejs-custom-es6-errors.md
@@ -17,7 +17,8 @@ module.exports = class AppError extends Error {
     // Saving class name in the property of our custom error as a shortcut.
     this.name = this.constructor.name;
 
-    // Capturing stack trace, excluding constructor call from it.
+    // Capturing stack trace, excluding constructor call from it
+    // (this is probably no longer required in node >=8, see the comments)
     Error.captureStackTrace(this, this.constructor);
 
     // You can use any additional properties you want.

diff --git a/nodejs-custom-es6-errors.md b/nodejs-custom-es6-errors.md
@@ -95,4 +95,4 @@ try {
 
 # Feedback
 
-It works great for my application, however cirtisim is welcomed.
+It works great for my application, however criticism is welcomed.
diff --git a/nodejs-custom-es6-errors.md b/nodejs-custom-es6-errors.md
@@ -14,11 +14,11 @@ module.exports = class AppError extends Error {
     // Calling parent constructor of base Error class.
     super(message);
 
-    // Capturing stack trace, excluding constructor call from it.
-    Error.captureStackTrace(this, this.constructor);
-
     // Saving class name in the property of our custom error as a shortcut.
     this.name = this.constructor.name;
+
+    // Capturing stack trace, excluding constructor call from it.
+    Error.captureStackTrace(this, this.constructor);
 
     // You can use any additional properties you want.
     // I'm going to use preferred HTTP status for this error types.

diff --git a/nodejs-custom-es6-errors.md b/nodejs-custom-es6-errors.md
@@ -21,7 +21,7 @@ module.exports = class AppError extends Error {
     this.name = this.constructor.name;
 
     // You can use any additional properties you want.
-    // I'm going to use preffered HTTP status for this error types.
+    // I'm going to use preferred HTTP status for this error types.
     // `500` is the default value if not specified.
     this.status = status || 500;
 

diff --git a/nodejs-custom-es6-errors.md b/nodejs-custom-es6-errors.md
@@ -11,7 +11,7 @@ I've tried to make it as lean and unobtrusive as possible.
 module.exports = class AppError extends Error {
   constructor (message, status) {
 
-    // Calling parent constrcutor of base Error class.
+    // Calling parent constructor of base Error class.
     super(message);
 
     // Capturing stack trace, excluding constructor call from it.

diff --git a/nodejs-custom-es6-errors.md b/nodejs-custom-es6-errors.md
@@ -0,0 +1,98 @@
+
+Here's how you could create custom error classes in Node.js using latest ES6 / ES2015 syntax.
+
+I've tried to make it as lean and unobtrusive as possible.
+
+# Defining our own base class for errors
+
+**errors/AppError.js**
+
+```js
+module.exports = class AppError extends Error {
+  constructor (message, status) {
+
+    // Calling parent constrcutor of base Error class.
+    super(message);
+
+    // Capturing stack trace, excluding constructor call from it.
+    Error.captureStackTrace(this, this.constructor);
+
+    // Saving class name in the property of our custom error as a shortcut.
+    this.name = this.constructor.name;
+
+    // You can use any additional properties you want.
+    // I'm going to use preffered HTTP status for this error types.
+    // `500` is the default value if not specified.
+    this.status = status || 500;
+
+  }
+};
+```
+
+# Defining specific error types
+
+**errors/EmailTakenError.js**
+
+```js
+module.exports = class EmailTakenError extends require('./errors/AppError') {
+  constructor (message) {
+    // Providing default message and overriding status code.
+    super(message || 'Specified E-Mail is already taken', 400);
+  }
+};
+```
+
+**errors/RequestValidationError.js**
+
+```js
+module.exports = class extends require('./AppError') {
+  constructor (fields) {
+    // Overriding both message and status code.
+    super('Request validation failed', 400);
+    // Saving custom property.
+    this.fields = fields || {};
+  }
+};
+```
+
+# Throwing and catching
+
+```js
+
+const AppError = require('./../api/errors/AppError');
+const EmailTakenError = require('./../api/errors/EmailTakenError');
+const RequestValidationError = require('./../api/errors/RequestValidationError');
+
+
+try {
+  // Throwing EmailTakenError exception.
+  throw new EmailTakenError();
+} catch (error) {
+  // Catching exception by class.
+  if (error instanceof EmailTakenError) {
+    console.log('E-Mail validation failed!', error);
+  } else {
+    // If failed to catch, throwing it higher.
+    console.log('Unknown error', error);
+    throw error;
+  }
+}
+
+
+try {
+  // Throwing RequestValidationError exception.
+  throw new RequestValidationError();
+} catch (error) {
+  // Catching error by base (parent) class.
+  if (error instanceof AppError) {
+    console.log('Some application error occurred!', error);
+  } else {
+    console.log('Unknown error', error);
+    throw error;
+  }
+}
+```
+
+# Feedback
+
+It works great for my application, however cirtisim is welcomed.
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