It is not hard to see that some people are struggling to handle errors, and some are even totally missing it. Handling errors properly means not only reducing the development time by finding bugs and errors easily but also developing a robust codebase for large-scale applications.

In particular, Node.js developers sometimes find themselves working with not-so-clean code while handling various kinds of errors, incorrectly applying the same logic everywhere to deal with them. They just keep asking themselves “Is Node.js bad at handling errors?” or "If not, how to handle them?” My answer to them is “No, Node.js is not bad at all. That depends on us developers.”

Here is one of my favorite solutions for that.

Types of Errors in Node.js

First of all, it is necessary to have a clear understanding of errors in Node.js. In general, Node.js errors are divided into two distinct categories: operational errors and programmer errors.

• Operational errors represent runtime problems whose results are expected and should be dealt with in a proper way. Operational errors don’t mean the application itself has bugs, but developers need to handle them thoughtfully. Examples of operational errors include “out of memory,” “an invalid input for an API endpoint,” and so on.
• Programmer errors represent unexpected bugs in poorly written code. They mean the code itself has some issues to solve and was coded wrong. A good example is to try to read a property of “undefined.” To fix the issue, the code has to be changed. That is a bug a developer made, not an operational error.

With that in mind, you should have no problem distinguishing between these two categories of errors: Operational errors are a natural part of an application, and programmer errors are bugs caused by developers. A logical question that follows is: “Why is it useful to divide them into two categories and deal with them?”

Without a clear understanding of errors, you might feel like restarting an application whenever an error occurs. Does it make sense to restart an application due to “File Not Found” errors when thousands of users are enjoying the application? Absolutely not.

But what about programmer errors? Does it make sense to keep an application running when an unknown bug appears that could result in an unexpected snowball effect in the application? Again, definitely not!

#node #node.js #error-handling