---
title: "Error Handling in JavaScript"  
description: "Error handling involves managing errors smoothly to ensure that your application can handle unexpected situations."  
author: "Ashutosh Patel"  
published: 2024-06-25  
updated: 2024-06-25  
canonical: https://www.mindstick.com/articles/336218/error-handling-in-javascript  
category: "javascript"  
tags: ["javascript", "javascript events", "erorr handing"]  
reading_time: 3 minutes  

---

# Error Handling in JavaScript

#### JavaScript Error Handling

[Error handling](https://www.mindstick.com/articles/1825/objective-c-error-handling) in JavaScript is an important part of writing robust and reliable code. It’s about handling errors nicely so that [your application](https://answers.mindstick.com/qa/97584/how-do-you-choose-the-correct-camera-for-your-application) can handle unexpected situations without crashing or being unwanted. Here is a detailed overview of error handling in JavaScript,

#### Types of Errors

**Syntax errors-** These are errors in code syntax, which make it impossible to parse and execute scripts.

```javascript
if (true {
   console.log("This is a syntax error");
}
```

**[Runtime Errors](https://www.mindstick.com/forum/159889/how-can-i-debug-javascript-runtime-errors-in-my-web-applications)-** These occur during execution of a script, such as trying to call a method on an [undefined variable](https://www.mindstick.com/forum/159891/how-can-i-resolve-undefined-variable-errors-in-javascript).

```javascript
let obj;
obj.method();  // Runtime error: Cannot read property 'method' of undefined
```

**[Logical errors](https://www.mindstick.com/forum/159543/describe-the-name-hiding-issue-in-c-plus-plus-and-how-it-might-lead-to-logical-errors)-** These are errors in the logic of the code that produce incorrect results but do not stop its execution.

```javascript
let total = 10 + "5";  // Logical error: total will be '105' instead of 15
```

#### Error Handling Mechanisms

Here are several types of handling errors in JavaScript as follows,

**try...catch...finally-** This is the basic way to [handle exceptions](https://answers.mindstick.com/qa/104815/how-to-handle-exceptions-in-pl-sql) in JavaScript. Code is executed in the `try` block, and if an error occurs, control is transferred to the `catch` block. The `finally` block is executed regardless of whether an error occurred or not.

## Syntax-

```javascript
try {
   // Code that may throw an error
} catch (error) {
   // Code to handle the error
} finally {
   // Code to run regardless of an error
}
```

## Example-

```javascript
try {
   let result = riskyOperation();
} catch (error) {
   console.error("An error occurred: ", error.message);
} finally {
   console.log("This will run regardless of an error.");
}
```

**throw Statement-** You can use a `throw` statement to create your own error.

## Syntax-

```javascript
throw new Error("Something went wrong!");
```

## Example-

```javascript
function checkAge(age) {
   if (age < 18) {
       throw new Error("Age must be at least 18");
   }
}
try {
   checkAge(15);
} catch (error) {
   console.error(error.message);
}
```

#### Custom Error Types

You can create your error types by extending the built-in Error class.

## Example-

```javascript
class ValidationError extends Error {
   constructor(message) {
       super(message);
       this.name = "ValidationError";
   }
}
function validateInput(input) {
   if (input < 0) {
       throw new ValidationError("Input cannot be negative");
   }
}
try {
   validateInput(-1);
} catch (error) {
   if (error instanceof ValidationError) {
       console.error("Validation Error: ", error.message);
   } else {
       console.error("Unknown Error: ", error.message);
   }
}
```

#### Asynchronous error handling

\
**Promises-** [Promises](https://www.mindstick.com/forum/160757/what-are-promises-in-javascript-and-how-do-they-work) have their own way of catch resolving debugging.

```javascript
someAsyncFunction()
   .then(result => {
       console.log(result);
   })
   .catch(error => {
       console.error("Promise error: ", error.message);
   });
```

**async/await-** When using async functions, you can handle errors with try...catch.

```javascript
async function fetchData() {
   try {
       let response = await fetch("https://api.example.com/data");
       let data = await response.json();
       console.log(data);
   } catch (error) {
       console.error("Async error: ", error.message);
   }
}
fetchData();
```

#### Best Practices

**Always Handle Errors-** never leave mistakes unchecked; Always use `try…catch` or promise `catch` blocks.\
**Provide Useful [Error Messages](https://answers.mindstick.com/qa/99815/how-can-you-diagnose-and-resolve-issues-with-application-crashes-or-error-messages)-** Make sure your error messages are clear and informative.\
**Log Errors Appropriately-** Use logging to track errors but avoid disclosing sensitive information.\
**Clean Up Resources-** The `finally` use blocking or other methods to clean objects (e.g. files or close [network connections](https://www.mindstick.com/articles/23267/establishing-network-connections-and-other-fun-things-to-do-with-ethernet-cables)).\

**Also, Read:** [Explation the concept OPPs in JavaScrpipt](https://www.mindstick.com/blog/304383/explain-the-concept-oops-in-javascript)

---

Original Source: https://www.mindstick.com/articles/336218/error-handling-in-javascript

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