Java script error codes | Java script error with examples

In JavaScript, error codes are typically associated with exceptions that occur during the execution of a program.

These error codes can provide insight into the nature of the error and help developers diagnose and fix issues in their code. Here’s a brief explanation of some common JavaScript error codes:

Java script error codes

SyntaxError:

This error occurs when the JavaScript engine encounters syntax that is not valid according to the language grammar. It often indicates a typo, missing parenthesis, bracket, or semicolon, or incorrect keyword usage.

// Example of SyntaxError - missing closing parenthesis
console.log("Hello World"; // SyntaxError: missing ) after argument list

ReferenceError:

This error occurs when trying to reference a variable or function that does not exist. It can also occur when trying to access a variable in an outer scope from within a nested scope where it’s not accessible.

// Example of ReferenceError - trying to access an undefined variable
console.log(nonExistentVariable); // ReferenceError: nonExistentVariable is not defined

TypeError:

This error occurs when an operation is performed on a value of the wrong type. For example, attempting to call a method on a null or undefined value, or performing arithmetic operations on non-numeric values.

// Example of TypeError - performing operation on a value of wrong type
let x = null;
console.log(x.toUpperCase()); // TypeError: Cannot read property 'toUpperCase' of null

RangeError:

This error occurs when a numeric value is not within the range allowed for a particular operation. For example, trying to create an array with a negative length or calling parseInt() with a string that cannot be parsed into a valid number.

// Example of RangeError - creating an array with negative length
let arr = new Array(-1); // RangeError: Invalid array length

URIError:

This error occurs when functions like encodeURI(), decodeURI(), encodeURIComponent(), or decodeURIComponent() are passed invalid URIs or URI components.

// Example of URIError - passing an invalid URI to decodeURI()
decodeURI('%'); // URIError: URI malformed

InternalError:

This error is thrown when an internal error in the JavaScript engine occurs. It’s usually not caused by the code itself but rather by a bug in the engine.

AggregateError:

Introduced in ECMAScript 2021, this error is a specialized error object that aggregates multiple errors into a single error. It’s commonly used in asynchronous operations that produce multiple errors.

// Example of AggregateError - creating an AggregateError with multiple errors
let errors = [new Error('First error'), new Error('Second error')];
throw new AggregateError(errors); // AggregateError: All promises were rejected

These examples illustrate common scenarios where each type of error might occur in JavaScript code. Handling these errors gracefully is essential for building robust and reliable JavaScript applications.

These error codes can help developers pinpoint issues in their code and take appropriate actions to handle them gracefully, such as displaying informative error messages to users or logging errors for debugging purposes.