JavaScript errors are one of the most common issues faced by web developers. They can be really frustrating, and often lead to long delays in site loading times. In this blog post, we’ll show you how to tackle different types of javascript errors, and how to make your code more error-free. We’ll also introduce the try…catch…throw and finally statement, By the end of this post, you’ll know everything you need to prevent errors from stopping your site from working properly.
Table of Contents
Types of Error
JavaScript errors can be caused by a variety of things, such as typos or missing semicolons. When errors do occur, error messages usually include the line number and column number where the error occurred. When you have a problem and can’t seem to solve it, try catch throw to catch errors in your code and provide a stack trace. This will help you identify the error and find a solution.
following are the most common type of javaScript error:
1.Syntax Error
If you’re getting error messages like “SyntaxError: Invalid syntax” when you try to run your code, there’s a good chance that you are making mistakes with the syntax of your code.
<script = "javascript"
console.log( ;
//missing closing paranthesis
</script> 2.Reference Error
Whenever you encounter a ReferenceError, it is important to take corrective measures. This error can be caused by incorrect arguments passed into a constructor function or when an object isn’t found where you were expecting it to be.
const x=console.log
const code = "code"
code //declared and exist
codeleaks //does'nt declared 3.Type Error
If you ever encounter a TypeError error in your JavaScript code, it will provide you with information about the type of error that occurred and how to fix it.
const no = 12.8
no.toLowerCase()
//raise error
//operation perform on wrong dataType 4.Range Error
RangeError is one of the most common errors JavaScript developers face. It can occur when you try to access a value that is outside of the range that your variable can hold.
const x = console.log
const array = [100,88]
array.length=100**1000
//range exceed the limit 5.URL Error
RangeError is one of the most common errors JavaScript developers face. It can occur when you try to access a value that is outside of the range that your variable can hold.
decodeURI("%")
//URIError: URI malformed 6.Runtime Error
Runtime errors are the most common type of JavaScript error. They can occur when the code runs too fast and doesn’t have enough time to finish processing everything correctly. This will likely stop the execution of the code, which gives you a chance to debug it more easily.
<script = "javascript">
console.screen();
//calling method that does'nt exist
</script> 7.Eval Error
EvalError is one of the most common JavaScript error types and can occur when trying to execute a script. Incorrect values passed to functions or variables are usually the root cause of eval errors. New version of JavaScript does not support eval() error.
8.Internal Error
InternalError is a built-in error message that is used when an error occurs within the JavaScript engine. This can be caused by problems with variables, strings, and arrays.
9.Logical Error
Logical errors are those problems with the relationships between values in your code. This can arise when you make mistakes with the syntax of your code, for example not using curly braces to declare a function or variable.
The Try...Catch...Throw And Finally Statement
When using the try…catch statement, make sure to include a finally block for handling any unwrapped exceptions. This javascript – function will help you fix the error and continue with your code. When encountering an error, try to use the try…catch statement to determine the root cause.
1.Try and Catch Block
Try and catch block is a conditional statement that helps to prevent errors from occurring. When you use try and catch, you can define a set of code blocks that will be executed if an error occurs.
function myFunc() {
var a = "codeleaks";
try {
alert("Value of string is : " + a );
}
catch ( e ) {
alert("Error: " + e.description );
}
} 2.Throw Statement
A throw statement in JavaScript is a code block that allows you to abort the current execution of a function or trigger an exception.
throw "text or string lenght is exceeding limit";
// throw a text
throw 1000; //throw number 3.The Finally Block
The finally block is a JavaScript construct that allows code to be executed regardless of whether or not any errors occur.
function myFunc() {
var a = "codeleaks";
try {
alert("Value of string is : " + a );
}
catch ( e ) {
alert("Error: " + e.description );
finally {
alert("Finally block will always execute!" );
}
}
} 4.Error() Constructor
The error() constructor is used to create an Error object. This object has properties that allow you to access details about the error, such as its code and location.
new Error("alert an error message") 5.Manually Throw and Catch Errors
you can use throw and catch statements to manually handle errors. When trying to debug an error without using try…catch, it can be difficult as the error message might not be clear or concise enough for you to understand what went wrong.
fetch ('https://www.codeleaks.io/')
.then (function(response){
console.log(response);
return response.jason();
})
.then (function(body)
{
console.log(body);
})
.catch(function(error)
{
console.log(error);
}) Also learn how to handle exception in javascript.
FAQs
Is there a better way to handle exceptions in my code than using try/catch blocks?
There may be a better way to handle exceptions in your code than using try/catch blocks. Throw can be used when you don’t care what kind of exception is thrown and when you want to prevent any exceptions from being caught at all.
What are some tips for avoiding common JavaScript errors?
There are a few things that you can do in order to avoid common JavaScript errors.
- Test your code before you publish it.
- Use the try/catch block.
- Use Error Management Tools.
- Check your syntax.
How can I ensure that my code runs correctly in all cases?
- Throw statements can be used in order to handle errors that may occur while executing your code. This way, you’ll know exactly what went wrong and where to find the error.
- A good rule of thumb is to use try/catch blocks to handle exceptions gracefully. This will allow your code to run correctly even if an error occurs while processing an object or array.
- make sure to use the right data types when working with arrays and objects. By doing this, you’ll avoid any errors and ensure that your code runs correctly.
Conclusion
JavaScript errors can occur at any stage of your code, so it’s important to be aware of the different types of errors and how to deal with them. In this blog, we have covered the try…catch…throw and finally statement and how it can help you deal with errors. Make sure to try out this technique and see the difference it makes in your code. Thanks for reading.
