JavaScript Errors

JavaScript errors, also known as exceptions, occur when the JavaScript engine encounters a situation that prevents it from executing the code correctly.
Understanding different types of errors in JavaScript is crucial for effective debugging and writing robust code.

Here are some common JavaScript errors:

Syntax Errors:
Reference Errors:
Type Errors:
Range Errors:
URI Errors:
Eval Errors:
Handling Errors:

Syntax Errors:

According to computer science, a syntax error is an error in the syntax of a sequence of characters or tokens that is intended to be written in a particular programming language or it is also a compile-time error if the syntax is not correct then it will give an error message.

Example

// Example of a syntax error: missing closing parenthesis
console.log("Hello, world!";

Reference Errors:

Reference errors occur when trying to access a variable or function that is not defined.

Example

// Example of a reference error: accessing an undefined variable

console.log(undefinedVariable);

Type Errors:

Type errors occur when an operation is performed on a value of an inappropriate type.

Example

// Example of a type error: using a method on a non-object

let str = "Hello";
str.push(" world"); // push is not a function

Range Errors:

Range errors occur when a numeric value is not within an allowed range.

Example

// Example of a range error: using an invalid array length
let arr = new Array(-1); // Invalid array length

URI Errors:

URI errors occur when using global functions incorrectly related to URIs (Uniform Resource Identifiers).

Example

// Example of a URI error: decoding an invalid URI component


decodeURIComponent("%");

Eval Errors:

Eval errors occur when using the eval() function incorrectly.

Example

// Example of an eval error: syntax error in evaluated code
eval("a+"); // SyntaxError: Unexpected end of input

Handling Errors:

You can use try...catch blocks to handle errors gracefully and prevent them from crashing your program.

Example

try {
  // Code that might throw an error
}catch (error) { 
  // Code to handle the error
}