TypeError in JavaScript

A TypeError in JavaScript happens when an operation is performed on a value of an unexpected type.

This could include attempting to perform arithmetic on a non-numeric string or calling a method on a null or undefined value.

For example, trying to use .length on a number would throw a TypeError because .length is a property of arrays and strings, not numbers.

One of the most frequent causes is trying to access or invoke a method on a variable that hasn't been properly initialized or is of the wrong type.

To fix this error, check the type of the variables involved using typeof or Array.isArray().

Ensure that variables are correctly initialized and validated before attempting operations on them.

Debugging TypeError often involves examining stack traces to identify which line or function triggered the error.

Additionally, you can use try...catch blocks to catch such errors during runtime, allowing you to handle exceptions gracefully without stopping program execution.

It's essential to validate user inputs or external data before performing operations to avoid such errors.

In modern JavaScript, strict mode ('use strict') can help prevent certain types of errors, making code more reliable and maintainable.