[MUST READ] Common JavaScript Errors and How to fix them?

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Javascript is a very important programming language for modern web applications and it supports a variety of frameworks and libraries. Getting errors is quite normal with such versatility but it gets quite irritating when the errors sound like an alien transcript.

Javascript seems quite easy and readable but the harsh reality is that Javascript is way more complex, efficient than any beginner’s interpretation. If you don’t trust me, ask someone you know, and have decent work experience in Javascript.

In this guide, you’ll learn about some of the most common java scripts errors. We also go through Uncaught Type Error and Try Catch Errors not working in Java fixes in detail.

It is requested to read about each of these errors thoroughly, it is because in the future if you’ll face these errors, you’ll just need a few moments to fix them.

Besides this, if you will carefully work with Javascript, chances are that you won’t get any of these common javascript errors in your application.

List of Common JavaScript Errors and Fixes

Below is a list other common JavaScript Errors you may incur when coding Java.

JavaScript ErrorFix for Java Error
Discord Javascript ErrorWhitelisting Discord Files in Antivirus Tool
Add in Feature Wizard
Clean Reinstall
Delete Discord Remaining Folders
Javascript Void (0)Ensure Java is Installed Correctly
Clear Cache
Remove Cookies in Browser
Enable Java in Browser
End of While Parsing Javascript Errorappend a closing or ending curly brace to a corresponding opened curly braces
Java Error Code 1618Restart Computer and reinstall Java
Restart Windows Installer Service msiexec.exe
Disable Antivirus Program
Install Offline Java
Java Error Code 1603 – Installation is not CompleteUpdate JavaScript
Uninstall Previous Version of Java
Use Offline Installer
Disable Java in Browser
Java Uncaught Type ErrorGenerally a Syntax or coding error – please refer below for details
JavaScript Try Catch Not WorkingGenerally a Syntax or coding error – please refer below for details

Uncaught Typeerror: ‘undefined’ is not a function

This the most common error that JS beginner gets because always tries to call a function that is not defined or improperly initialized until that scope.

If you’ll look for the solution on the internet, you might get confused with the term “uncaught type error is not a function”, but actually this term is used to refer the “Uncaught Typeerror: ‘undefined’ is not a function” error only.

Besides this, after this guide, I don’t think you will have to look on the internet for solutions.

Here if you will see, the particular code will give an error:

alert(message());

var message = function(){

return ‘Hello World !’

};

It is because the message() function is being called without its deceleration. Here interpreter will think that message is not a function it will throw the error on your screen.

Whereas, if you will execute this code, you won’t run into any error:

var message = function(){

return ‘Hello World !’

};

alert(message());

This “Uncaught Typeerror: ‘undefined’ is not a function” error, totally depends on how and where you are defining the functions and calling as well.

If you will at another example,

message();

function message() {

show();

}

var show = function() {}

The above piece of code will throw the error, whereas, the following piece of code won’t throw any error.

message();

function message() {

show();

}

function show() {}

Now you might be confused here and must be thinking, in both the examples, the function is declared after it’s called but still, there won’t be any error.

It is because of the “Hoisting” technique that Javascript uses while interpreting the script. Now, you are not aware of Hoisting, then let me quickly brief you about it.

“Hoisting a technique where interpreter of Javascript automatically move the declaration of variable and functions to the top of the script, but the catch here is all the functions that are declared using expression are excluded”

Tip: Be very careful while declaring the functions and selecting their way of declaration.

Javascript try-catch not working

This is not an exact error but I have seen beginner hitting this query on the programming community.

Most of them report this exact statement “Javascript try catch not working”. So, in this section, we will have a look at all the basic aspects of the JS try-catch block.

Try-catch block of Javascript  looks like this:

            try{

//statements

}

catch (e){

//statements

}

Here, the “try” block is first executed and if the interpreter detects no error then the catch block is ignored and control is passed to the next statement after the “catch” block.

Besides this, if any error is detected then the interpreter will throw an exception that will be stored in the “e” object. It is because wherever an exception is thrown, it is in the form of an object and it has all the basic information related to the error. For instance, it will have an error message, name, and stack.

It depends on the developer, which one he/she accesses.

For instance,

try{

}

catch(e){

alert(e.name); //name of the error will be displayed

alert(e.message); //error details will be published

alert(e,stack); //current call stack will be displayed

}

Instead of this, if the developer wants, he/she can even display all the error details with name, message, and stack using a single statement also i.e.

alert(e)

Apart from this, with the help of “throw”, developers can push their own error objects. They can use conditional statements to filter out the wrong inputs and can raise exceptions using the “throw” keyword.

While implementing the try-catch block, developers must note that the try-catch block will only detect the run-time errors, if incase the scrip has some syntactical error then chances are that try-catch block won’t work.

Being a Javascript developer, you have to write your script very consciously, detecting error manually can be very tricky sometimes.

JS is not like C or C++ where you will be provided all the necessary data including the line number and exact location to debug. Here error messages are very complex and provide limited information.

Fixes for Errors in JavaScript Summary

Javascript developers mostly face problems with “Javascript undefined errors” and these errors occur due to the carelessness of the programmer. There is no specific solution to these “undefined errors”, the developer just has to be alert while writing the script.

For the majority of Javascript developers, debugging on Javascript is very difficult. Mainly, it is because they don’t understand the errors when they pop up. If you want to be a good Javascript developer, you can’t skip debugging and in order to debug efficiently, you have to study the errors and their fixes.

I hope this guide about common javascript errors gave you an exact idea about How easy it is to debug the error once you understood. Remember, in Javascript, understanding the errors is the most complex yet most crucial aspect. In the initial phase always prefer investing more time studying the basics of the language than implementing its programmings. Once you have created a base then writing programs won’t be tough for you.

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