Managing Errors In JavaScript How To Fix It

Errors in programming are unavoidable. Your application will eventually exhibit some unexpected behaviour. When something goes wrong in your code, JavaScript raises errors just like any other programming language. Errors stop an application’s regular flow. However, they also aid in safeguarding your application from erratic behaviour. It’s critical to understand correct error handling techniques.

Why Is Error Handling Important?

An enhanced user experience is facilitated through error management. You can replace JavaScript’s standard and occasionally verbose errors with your own, more legible error messages. Some mistakes can be handled gently so that your software continues to execute rather than crash. Additionally useful throughout development is error handling.

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Catching a runtime error allows you to take action with it, such as logging it to the browser console. This is more gracious than an error leading to a crash and leaving you unsure of how or why it happened.

Structure of JavaScript Built-In Errors

Errors in JavaScript are objects having three characteristics:

  • Name: The mistake has this name. For instance, a missing variable name will result in the SyntaxError error.
  • The message’s body, which provides a written explanation of the mistake, appears here.
  • cause: To keep track of the call stack, use this property with custom errors.
Managing Errors In JavaScript How To Fix It
Managing Errors In JavaScript How To Fix It

Common Types of Error in JavaScript

Here are a few typical JavaScript mistakes.

Syntax Mistake

When JavaScript tries to interpret your code, syntax mistakes may happen. If the syntax of your code is incorrect, an error will be raised. Typical mistakes that might cause syntax issues include:

  • variable names are absent.
  • an empty space following a function.
  • ” is missing following a condition.


When a software tries to reference a variable that is not available or within its range, reference errors happen.


When JavaScript is unable to complete an operation because the type it expects is different from the one it obtains, it may raise a type error.


If a global URI handling function, such as decodeURIComponent(), is used incorrectly, an error will result. The encoding or decoding fails as a result.


This mistake is a representation of several errors rolled into one. When you wish to throw numerous mistakes at once, use it. When all of the promises supplied to Promise.any() reject, for instance, it may raise an AggregateError().


When a problem arises within the JavaScript engine, an InternalError is thrown.


The range of values you can send as parameters is limited for some functions. If you attempt to pass a value that is outside of that range, you will receive this error.

Error Handling With the Try…Catch Block

The try…catch…finally block in JavaScript comes with built-in exception handling capabilities. Using the toss operator, you can also raise your own errors. A try…catch block can be used to deal with runtime errors. In the try block, you write accurate code that you anticipate running successfully. You can create code to handle errors in the catch block.

If the try block’s code produces no problems, the catch block is not used. The catch block is where execution moves if it produces an error. Regardless of whether an error happens, the finally block’s code executes. If you don’t require this block, leave it out of the document. The try block’s code must include valid code. JavaScript will throw a parser error if it isn’t. This programme tries to log the text variable’s value.

As a result of the variable’s lack of definition, the programme will crash. The catch block prints this error to the console. The finally block then executes and prints its own message. The getData() function is used in this example, and the programme assigns the output to the data variable. If the data in the try block is empty, the block throws a specific error. This error is caught by the catch block, which logs it to the console.

Throwing mistakes is a great development tool. The customised error message can help you figure out why your programme isn’t performing as you expected it to. You can use a string for the error object, as this example shows. Any JavaScript expression can actually be thrown as an error. However, use a JavaScript object with a name and message to maintain compatibility with built-in errors.

Extending the JavaScript Error Object

When addressing mistakes that don’t correspond to the objects that JavaScript already provides, a new error class comes in handy. For instance, you could want to create a special type named ValidationError to isolate data validation errors.

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Errors Are There to Help

Regardless of the language you use, error handling is an essential component of programming. JavaScript offers excellent support for throwing and catching exception-style errors. Additionally, it contains a number of built-in error kinds that you may manage and apply to your own situations. When writing JavaScript in “sloppy mode,” some problems, such as syntax errors, may go undetected. JavaScript can detect problems that it might have otherwise missed by using strict mode.

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